Abstract:
Emergency egress systems carry multiple riders simultaneously accessing zip line catenary from higher, inaccessible, working locations to lower, safer areas. Hangers above the track line suspend trolleys to avoid weighting the catenary unduly at the high end, which might otherwise alter (reduce) clearance distances and safety of riders above a launch platform (deck). Catenary shape is controlled against approaching a launch deck by sequencing the release from the hangers of each trolley to roll along the catenary with its own rider. Autonomous braking, inter-trolley bumpers, and vertical stabilizers enable each rider to quickly occupy a seat (harness, etc.) and launch onto the track line, unconcerned with riders ahead or behind until underway. Multiple trolleys may thus load, launch, and in close proximity on a single line, regardless of the total weight of multiple riders.

Description:
RELATED APPLICATIONS 
       [0001]    This application: is a continuation in part of U.S. patent application Ser. No. 15/354,866, filed Nov. 17, 2016, which claims the benefit of Provisional Patent Application Ser. No. 62/257,610, filed Nov. 19, 2015; and is a continuation in part of U.S. patent application Ser. No. 14/923,708, filed Oct. 27, 2015, all of which are hereby incorporated by reference. This application also incorporates herein by reference the following applications and patents: U.S. patent application Ser. No. 14/451,932, filed Aug. 5, 2014; U.S. patent application Ser. No. 14/711,465, filed May 13, 2015; U.S. Provisional Patent Application Ser. No. 62/058,544, filed Oct. 1, 2014; and U.S. patent application Ser. No. 14/923,708, filed Oct. 27, 2015. Moreover, this application hereby incorporates herein by reference U.S. Pat. No. 7,637,213, issued Dec. 29, 2009; U.S. Pat. No. 7,966,940, issued Jun. 28, 2011; U.S. Pat. No. 7,299,752, issued Nov. 27, 2007; U.S. Pat. No. 7,404,360, issued Jul. 29, 2008; U.S. Pat. No. 6,622,634, issued Sep. 23, 2003; U.S. Pat. No. 6,666,773, issued Dec. 23, 2003; U.S. Pat. No. 8,191,482, issued Jun. 5, 2012; U.S. Pat. No. 8,333,155, issued Dec. 18, 2012; and U.S. patent application Ser. No. 14/451,932, filed Aug. 5, 2014. 
     
    
     BACKGROUND 
       [0002]    Field of the Invention 
         [0003]    This invention relates to emergency egress systems and, more particularly, to novel systems and methods for rapidly evacuating an area of multiple workers using a zip line. 
         [0004]    Background Art 
         [0005]    The word “zipline” and words “zip line” refer to a line, such as a wire rope, steel cable, fiber rope, or the like as a “track line,” typically suspended as a catenary between two supports. A catenary is a well defined and understood term in structural and civil engineering, used here in that ordinary meaning. 
         [0006]    A zip line necessarily contains no intervening supports. It typically relies on gravity, although some short lines may be more level. Some lines lacking sufficient (or having zero) decline between a start point and end point may rely on a rider. A rider or riders may move the trolley by drawing on the track line directly, or drawing on a nearby and nearly parallel line, by hand-over-hand grasping and pulling on the appropriate line. That motion is relative, whether the cable is fixed or not. All lines may be fixed at their ends. Lines may be run around pulleys at each end. In some instances, an attendant on the ground below a zip line may draw a rider and trolley along a zip line. Such attendants may draw a rider on an uphill portion near the lower end thereof, in order to move the rider along. An attendant may apply a braking force on a moving rider and trolley. 
         [0007]    Adventure stories, action movies, military operations, and the like may rely on zip lines as lightweight, temporary mechanisms for crossing a space, such as a river or gorge. An individual rider may use a gloved hand for their own braking. One may move along a cable or line by grasping the overhead line with a gloved hand. In other instances, a long braking rope extends downward to be grasped at an appropriate time and place by an operator below. The operator grips the rope to restrain or to exert force on a rider, thereby slowing the rider from crashing into the lower anchor on the ride. 
         [0008]    Frequency of use, rider ability, panic, skill, comfort with speed, or the like, and the presence of multiple riders accessing, launching, and riding seats simultaneously create risks affecting operation and safety. Overweighting a catenary near a single location distorts its shape, altering clearance above a deck or other surface therebelow. This creates problems for riders needing to stage loading and launching from a pre-determined height of a deck structure. 
         [0009]    In addition, zip lines have traditionally been a solo ride device. Brakes accessible to a rider have been largely absent. Absent, and now needed, is an ability to control an individual trolley on a track line, and safely accommodate short distances and possible impacts between trolleys of multiple riders loaded, launched, and rolling simultaneously on a single line from a single loading deck. 
         [0010]    What are needed are apparatus, systems, and methods to render practical, safe, reliable, and consistent the unattended use of multiple trolleys launching simultaneously from a single loading deck to rapidly load and carry away workers from a location that has suddenly become dangerous, where time is of the essence and conventional exit is not practical. 
       BRIEF SUMMARY OF THE INVENTION 
       [0011]    In view of the foregoing, in accordance with the invention as embodied and broadly described herein, a method and apparatus are disclosed in one embodiment of the present invention as including a set of anchors, which may be secured atop towers or elevated positions calculated to provide clearance above underlying foliage and terrain. The towers may operate as spacers away from obstructions below that might interfere with or injure a rider. 
         [0012]    A platform at an upper tower and cable or anchor for launching and a corresponding lower platform, tower, and anchor for landing are provided with each zip line. Secured to and by each tower is a line, typically a wire rope as that term is understood in the engineering and manufacturing art. Industry has long used woven strands of twisted wire having comparatively high strength and a comparatively low elongation under load. Sometimes the term “cable” refers to a bundle of electrical wires. Not here, because cable is not an improper term for a wire rope. A cable acts as a track line, typically suspended in a catenary shape between two anchors (e.g. towers). All points along a track line between two towers may be free of intermediate supports. In some embodiments, hardware may permit cable supports to be traversed by a trolley on the cable. Here, typically, a vertical stabilization system may limit any dropping or drooping of a track line in response to weighting by multiple riders simultaneously at a single launch deck. 
         [0013]    Cables as track lines may be monotonically tilting downward, may be level, or may be freely suspended with upward and downward angled portions of a catenary suspension. An upper anchor will serve as a launch location while the lower anchor will be associated with the landing location. 
         [0014]    In one embodiment of an apparatus and method in accordance with the invention, a launch platform has associated therewith a deck on which a user may comfortably stand or move about. A launch block secured to the main track line or carrier (cable, wire rope) is responsible to register a trolley mechanically and electronically for launching from the launch platform. 
         [0015]    Similarly, a landing platform may be configured with a deck on which a rider may disembark from the harness or seat suspended from a trolley on the overhead track line. A velocity or momentum attenuator may exist approaching the terminal or landing platform in order to brake the speed of a rider approaching that platform. 
         [0016]    The procedure of operation is sufficiently simplified that there is comparatively little to remember. Thus, a simple process, straightforward training, and riders may move quickly in an emergency situation to a launch deck, load into a seat or harness, launch when ready, and travel in close proximity Trolleys may run independently, yet may create a virtual train of trolleys running in close proximity or even touching. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The foregoing features of the present invention will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only typical embodiments of the invention and are, therefore, not to be considered limiting of its scope, the invention will be described with additional specificity and detail through use of the accompanying drawings in which: 
           [0018]      FIG. 1  is a perspective view of upper and lower stations for launching and landing, respectively, in a system in accordance with the invention; 
           [0019]      FIG. 2  is a perspective, exploded view thereof, showing various optional readers and corresponding targets suitable for use in the upper and lower stations; 
           [0020]      FIG. 3  is a perspective view of a rider in harness, and illustrating various types of targets that may be associated singly or together with a rider using a system in accordance with the invention; 
           [0021]      FIG. 4  is a perspective view of a trolley in accordance with the invention, illustrating a launch block, not yet registering the trolley in its secured position, and the trolley being connected in an exploded view to alternative embodiments of harnesses; 
           [0022]      FIG. 5  is a perspective view of a trolley of  FIG. 4 , in accordance with the invention, illustrating a launch block now registered with the trolley in its secured position; 
           [0023]      FIG. 6A  is a left side, perspective view of a trolley having a launch block interlock system in one alternative embodiment thereof; 
           [0024]      FIG. 6B  is a left side elevation view thereof; 
           [0025]      FIG. 6C  is a rear elevation view thereof; 
           [0026]      FIG. 7  is right side perspective view thereof; 
           [0027]      FIG. 8A  is a lower quarter, left side, perspective view of an alternative embodiment of an interlocking trolley with the brake system closed; 
           [0028]      FIG. 8B  is an upper quarter, left side, perspective view thereof with the brake system (caboose) open; 
           [0029]      FIG. 8C  is a rear, upper quarter, left side perspective view thereof; 
           [0030]      FIG. 8D  is an upper quarter, rear perspective view thereof; 
           [0031]      FIG. 8E  is a left side elevation view thereof; 
           [0032]      FIG. 8F  is a rear elevation view thereof; 
           [0033]      FIG. 9A  is a top plan, cutaway view of one embodiment of a latch mechanism securing a trolley to a launch block; 
           [0034]      FIG. 9B  is a frontal, upper quarter, left side perspective view of a snap shackle on an arm for interlocking the trolley to a launch block; 
           [0035]      FIG. 9C  is a top plan, cutaway view of an alternative latch and release mechanism for securing a trolley to a launch block. 
           [0036]      FIG. 10  is a perspective view of one embodiment of a pair of trolleys not yet engaged to run together, one braked by an operator and one unbraked by itself, but controlled by movement of the braked trolley; 
           [0037]      FIG. 11  is a right side elevation view thereof, with the two trolleys engaged and in contact to operate together; 
           [0038]      FIG. 12  is a right side elevation view of a system wherein a single braking trolley is operated to brake a series of unbraked trolleys running therebehind; 
           [0039]      FIG. 13  is a right side elevation view of a system of trolleys, wherein a braked trolley trails behind multiple unbraked trolleys connected thereto and running in front thereof; 
           [0040]      FIG. 14  is a right side elevation view of a braked trolley having unbraked trolleys running both ahead and behind, connected to be controlled by operation of the braked trolley; 
           [0041]      FIG. 15  is a rear perspective view of a trolley suitable for an emergency egress system in accordance with the invention; 
           [0042]      FIG. 16  is a side elevation view of one embodiment of an emergency egress configuration in accordance with the invention; 
           [0043]      FIG. 17  is a perspective view thereof; and 
           [0044]      FIG. 18  is a perspective view of an emergency egress system of  FIGS. 16 and 17  equipped with a harness seat for operation. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0045]    It will be readily understood that the components of the present invention, as generally described and illustrated in the drawings herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the system and method of the present invention, as represented in the drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of various embodiments of the invention. The illustrated embodiments of the invention will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. 
         [0046]    A zip line may extend as a catenary, as defined in the engineering art. The term “catenary” is understood by repair to any textbook on structural mechanics or engineering nomenclature. The catenary extends freely between end supports. It may suspend from an upper anchor point to a lower anchor point, the decline of the line providing the gravitation motivation of a rider suspended from a trolley. The trolley may be as simple as a single wheel or pulley in a frame, from which frame is suspended a harness, seat, handle, or the like by which a rider is supported. 
         [0047]    Zip lines may simply be deployed, lightweight, temporary mechanism for crossing a space that is otherwise resistant to traverse. For example, crossing a river, gorge, or the like, a zip line may provide for transport of materiel, personnel, and so forth. Zip lines have a few inherent difficulties in installation and operation. For now, the details of installation are not of concern with respect to the instant application. 
         [0048]    On the other hand, the difficulties of operation are substantial. For example, a soldier trained to use a zip line may undergo hours or days of training. An individual who relies on zip lines in an industrial, military, or other routine context will not only have trained intensely but will have extensive experience. 
         [0049]    However, in recent years, zip lines may have utilitarian function or an entertainment function. Children&#39;s youth camps, Boy Scout™ camps, high-adventure camps, “challenge courses” offered by industry to executive teams for team-building purposes, amusement parks, ski resorts looking for additional amusements that do not require snow, and so forth are possible locations for installing zip lines. 
         [0050]    To a certain extent, the amusement-ride-type, zip lines may have obtained their most significant start in second and third world countries where manual labor was more readily available. For example, it is not uncommon to have an individual rider responsible for their own braking to slow their descent on a zip line by grasping the overhead line with a gloved hand. In other instances, a long braking rope extends downward to be grasped at an appropriate time and place by an operator below. The operator grips the rope to restrain or to exert force on a rider, thereby slowing the rider from crashing into the lower anchor on the ride. 
         [0051]    Herein are described several embodiments of zip lines, including as amusement rides, canopy tours, and emergency egress systems. Herein, a reference numeral refers to a particular type or class of item that can be named. A reference numeral followed by a trailing letter refers to a specific instance of the numbered item. Accordingly, it is proper to use a number without a trailing letter to indicate a particular type of item or class of item. A number used with a specific trailing letter indicates a particular instance of the item, so identified in a figure. 
         [0052]    Referring to  FIG. 1 , a system  10  in accordance with the invention may include an upper station  12  from which riders will launch on a zip line ride. In the illustrated embodiment, an upper station  12  includes a safety structure  13 , such as a railing  13 , fence  13 , or the like. The railing  13  surrounds virtually on all sides, an upper deck  14 . The exit for launching a trolley may have a net, gate, or both to provide proper egress but assure safety against falling from the deck  14 . The upper deck serves as the staging space  14  for a rider to harness up, clip in to the system  10  and launch on a descent. 
         [0053]    As illustrated, the upper deck  14  may be formed of any suitable material, such as expanded metal, deck planking, concrete, or the like. Various embodiments of systems  10  in accordance with the invention are identified in the U.S. Patents and Applications incorporated hereinabove by reference. Various embodiments for decks  14  or platforms  14  serving as upper stations  12  are illustrated and detailed. 
         [0054]    In the illustrated embodiment, a railing  13  is important if and when the system  10  is unattended. Instead, users (riders) are trained, their decisions are limited, and their equipment is modified in order to assure user safety. Accordingly, users are restricted by various mechanical and electronic interlocks from improperly entering or exiting a station  12  or launching from the station  12 . A station  12 , absent the proper authorization, safety checks, and so forth, will not permit a user to enter therein and launch therefrom. 
         [0055]    As a user approaches the upper station  12  a reader  15  may be provided as part of an electronic portal  16 . This entry portal  16  may require identification, authorization, and so forth as described hereinbelow. 
         [0056]    The upper station  12  may include an access control  17 , such as a turnstyle  17 , or the like. Various embodiments of a system  10  in accordance with the invention may count, track, control, and report on the specific locations of various users operating within the system  10 . 
         [0057]    Thus, in some embodiments, the turnstyle  17  may be required. Alternatively, another barrier  18  or gate  18  may be the access control. In certain embodiments, the portal  16  will be required for entry through a physical barrier  18  after which a turnstyle  17  or other access control  17  may count, track, register in, and so forth a user. 
         [0058]    The actuator  19  or bar  19  of the turnstyle  17 , if conventional, may not serve as an absolute physical barrier  18 . Thus, either, or both, in series, may be relied upon in the system  10 . However, the actuator  19  may be defeated in an unattended system. For example, subway systems, mass transit rail systems, and so forth often use turnstyles  17  as an entry and exit mechanism, including control by card readers, and so forth. However, such systems are all attended. Various transit authority police, station attendants, and the like as well as a large public population will notice and report any breaches or other violations. 
         [0059]    In contrast, in an apparatus and method in accordance with the invention, the system  10  may be remote, and completely unattended for extended periods of time, including hours, possibly days, but probably inspected at least weekly. In most circumstances, one would expect to have a safety check by personnel perhaps daily, traveling through the system  10  on all the routes. However, this takes an extensive period of time, and need not be done every day. However, prudence would suggest at least weekly inspections. 
         [0060]    Since the system  10  is unattended for extensive periods of time, and since zip lines over ravines, rivers, forests, and other scenic sites are inherently life-or-death situations, safety requires protection that cannot be defeated. Thus, the fence  13  may actually be higher than an individual can access or climb, and may be protected by security devices, concertina wire, or the like against incursion by unauthorized individuals. 
         [0061]    For example, remote systems  10  will not likely be defeated by paying customers as riders, properly equipped, trained, and authorized to access the system  10 . However, it is not unknown to have complete strangers access a zip line with makeshift equipment, and cause harm to the system  10 , as well as personal danger, injury, or worse. Therefore, the presence of an absolute physical barrier  18  as well as the access control  17  is not actually a redundancy. Thus, by urging the actuator  19  forward, a user (rider) may rotate a turnstyle  17 , thus gaining proper access, recording an account or access number associated with the rider, the trolley, or both, and so forth. 
         [0062]    A track line  20  is connected between towers, and suspends therefrom as a catenary  20 . The patent documents incorporated hereinabove by reference lay out detailed structures and methods for establishing anchors, towers, bollards, and the like for a track line  20 . The track line  20  is typically formed of a wire rope of suitable dimensions, typically from about three quarters inch to about one inch in diameter. Nevertheless, shorter spans support less weight, and therefore may rely on smaller diameters. Likewise, longer spans may be correspondingly larger. 
         [0063]    The track line  20  originates near the upper station  12  such that the track line  20  passes directly over the upper deck  14 , at a height providing safe access to a user (rider). Ultimately, the track line  20  also descends (always with a downhill slope) to a lower station  22 . The lower station  22  is similar in construction to the upper station  12 , to include a fence  23  or railing  23 , a lower deck  24 , and one or more readers  25 , associated with an electronic portal  26 . Again, the lower station  22  may include an access control  27 , such as a turnstyle  27 , and a physical barrier  28  or gate  28 . An actuator  29  or bar  29  on a turnstyle  27  is simply one mechanism by which to detect that a user has exited. Others may operate including reader  25  and reminder  29  affirmatively engaging a user. 
         [0064]    An important reason for an actuator  29  on a turnstyle  27  is to obtain a report without requiring or relying exclusively on memory or training of a rider. Certain protections and interlocks within the system  10  will prevent accidentally loading a single line  20  with multiple users. Similarly, a rider will not be permitted to leave the upper station  12  until the lower station  22  is clear. Thus, it is just as important for a rider to check in with a reader  25  at a lower electronic portal  26  to check in through activation of a reader  15  in an upper portal  16 . The turnstyles  17 ,  27  also indicate rider locations. Passing through a turnstyle  17 ,  27  indicates that an individual has entered or exited the respective deck  14 ,  24 . Certain provisions may be made for various portals  16 ,  26  at different locations in order to more specifically identify where exactly users are located. For example, if multiple riders are allowed on a deck  14 ,  24 , they may be required to remain at registered locations away from the path of a trolley and rider actively moving along the track line  20 . 
         [0065]    For example, the system  10  has been integrated and simplified for users sufficiently that children may be able to operate as riders of the system  10 . However, physical height is a limitation that cannot be readily overcome. Thus, a man nearly six feet tall or a woman of corresponding stature may be able to reach a track line  20  from a deck  14 ,  24 . However, a child a foot or less shorter in height cannot. To that end, stairs, steps, risers, or the like may be added to the deck  14 ,  24  in order to permit a smaller use to clip in to the track line  20 . 
         [0066]    Alternatively, an associated adult may be permitted access to assist. A parent or adult chaperone may be permitted on the deck  14 ,  24 , so long as verification is provided that such an attending, related, responsible adult is sufficiently clear of the path under the track line  20  when riders are coming and going. 
         [0067]    Thus, the electronic portals  16 ,  26  may permit multiple persons to be on the decks  14 ,  24  at any given time, but may require that all adults other than the designated rider be remote from the track line  20  any time a rider is underway thereon. Thus, when the trolley is stopped at the upper deck  14  or the lower deck  24 , then a responsible, chaperoning adult may approach to assist in clipping in and unclipping a child rider. 
         [0068]    Various additional equipment is installed about the stations  12 ,  22 . For example, a cable gate  30  or cable close gate  30  serves as an electronically actuated, mechanical interlock  30 . The cable close gate  30  is a mechanical system that preferably blocks any ability of a user  45  to travel down the track line  20 . The gate  30  effectively arrests anything traveling along the track line  20  against leaving the upper station  12 . A gate  30  may operate in any of several manners. 
         [0069]    For example, a yoke that simply sits on the line  20  will serve this function. Likewise, a hook, a plate-shaped shield may serve. A plate, cone, ball, or other obstruction, having an aperture or slot in the bottom thereof, may be activated to slide down over the line  20 . With the line  20  occupying the slot, the obstruction provides a stop against any access to the track line  20  or at least any movement downward therealong. 
         [0070]    In other embodiments, a physical obstruction  30  of any type in close proximity to the track line  20  preventing passage therealong will serve. The shape is less important than the proximity to the track line  20 , in order that no sliding or rolling member can pass. For example, a rectangular plate with a slot or aperture protruding from a bottom edge to about the center thereof may block the line  20 . Similarly, a spherical obstruction having a slot between a lower edge and a center thereof may be placed over the line  20 . 
         [0071]    In another embodiment, a hook or latch may engage the top, bottom, or other location on any material or fixture attempting to travel along the line  20 . In another embodiment, a simple bar or rod may pass horizontally under the line  20  at a distance and of a length calculated to prevent any suspended item from passing along under the line  20 . Any combination of rods, plates, spheres, solids, hooks, wedges, or the like pivoting or translating into position increases cross sectional area. Any such mechanisms may be used to assure that no unauthorized structures may pass along the line  20  out from the upper station  12 . 
         [0072]    The significance of the cable close gate  30  is primarily safety. Unauthorized access to the line  20  at any time, by any person, for any reason may risk damage to the line  20  or other parts of the system  10 . However, the highest risk of loss, damage, or injury is to any person who accesses the line  20  without authorization. Serious injury or death may occur as a direct consequence of unauthorized access. Accordingly, a system  10  that does not require a plethora of attendant technicians managing and instructing riders at the upper station  12 , lower station  22 , or both militates in favor of serious efforts at locking out unauthorized persons for their own safety. 
         [0073]    Referring to  FIGS. 1 through 5 , and to  FIGS. 1 through 18 , generally, also at the upper station  12  is a launch block  32 , certain embodiments of which are disclosed herein. Others are disclosed in the references incorporated herein by reference. The launch block  32  is responsible for registering, meaning mechanical registration, electronic registration, or both, of the trolley  50  of any rider  45 . 
         [0074]    The launch block  32  is provided with certain fixtures and fittings that meet in a mating relationship with components used by the rider  45 . Accordingly, mechanical registration assures that the mechanical interlocks are closed, are properly located, and that a user  45  may properly operate the system  10 . Likewise, certain sensors in the launch block  32  provide electronic interlocks that report (to a master controller  40  (computer) the proper registration in space, and therefore the proper registration with suitable control systems in order that launch from the upper station  12  is authorized and enabled. 
         [0075]    Meanwhile, a terminal detector  34  may optionally detect passage of a user  45 . Nevertheless, in most embodiments, the incoming portal  16  and its reader  15 , the outgoing portal  26  and its reader  25 , and various optional sensors and controls on the barriers  18 ,  28 , turnstyles  17 ,  27 , and the like may report access by users, entry, and exit, and control them to promote safety. 
         [0076]    Referring to  FIG. 2 , a power source  33  or power line  33  may be provided for various readers  15 . Readers  15  may take on various embodiments. For example, a reader  15   a  may operate as a radio frequency detector, such as RFID reader systems  15   a . In such a system, a target  35   a  may be read by way of a sensor  37   a  communicating over a network  36  connected by a communication link  38 . Thus, the communication link  38   a  connects the reader  15   a  to the network  36 . The signal from the sensor  37   a  may be processed by the reader  15   a , or may be simply transmitted or read. 
         [0077]    Ultimately, a master controller  40  includes a computer system, tasked with receiving incoming data  42  from monitoring the portals  16 ,  26  and the readers  15 ,  25 . Similarly, additional sensors may be provided, as well as local controllers, actuators, and detectors (like those described herein) for the access controls  17 ,  27  and the physical barriers  18 ,  28 . 
         [0078]    By the various modes of operation, signals from all sensors in the foregoing and other components may be transferred. They arrive as monitoring data  42  or incoming data  42  received by the master controller  40 . 
         [0079]    After processing the incoming data  42 , the master controller  40  provides commands  44  or authorization  44  back to various devices in the system  10 . For example, actuators and locks may be opened or enabled for the access controls  17 ,  27 , the physical barriers  18 ,  28 , as well as the cable close gate  30 , the launch block  32 , and so forth. Detectors  34  typically need not have any controls associated therewith. That is, there is no need for a command to be received by in every embodiment of the detector  34 . Such straightforward functionality as turning on, turning off, polling, reporting, and the like may be programmed to involve commands sent to detectors  34 , such as the terminal detector  34 . Nevertheless, in other embodiments, the detector  34  may simply report a signal when polled. It may report activity on an interrupt basis as in various modern digital computer systems. 
         [0080]    Referring to  FIGS. 2 and 3 , the readers  15 ,  25  may be implemented in any of the embodiments illustrated in  FIG. 2 , or others. For example, the reader  15   b  relies on a card  35   b  such as a magnetic card in order for a sensor  37   b  to detect data from the magnetic card  35   b . Suitable power sources  33 , such as a line  33   a ,  33   b , or a battery, or the like may serve to power the reader  15  and the communication link  38 . 
         [0081]    One should note that it is proper herein to speak of any reference numeral alone, with any trailing alphabetical character, or both. That is, a reference number refers to a named item. A trailing reference letter refers to a specific instance of the item designated by the reference numeral. 
         [0082]    Referring to  FIG. 3 , a rider  45  may be provided with a harness  46 , helmet  47 , and some securement  48 , to any of which may be secured one or more targets  35  or passes  35 . For example, in the illustrated embodiment, beginning clockwise from the top of the illustration, a target  35  may be replaced on the top of a helmet  47  to be read by a detector  37  or sensor  37  above the user  45 , and having a field of view therebelow. 
         [0083]    As another example, laser bar code readers  15  use a coherent beam of light, and may therefore read codes at a considerable distance on a target  35  or pass  35 . Thus, such readers  15  above a user  45  passing through a portal  16 ,  26  may automatically detect and report a location and time of a user  45  identified by the target  35  or pass  35 . 
         [0084]    The target  35  on the side of a helmet  47  may operate in much the same manner. Also, in systems such as radio frequency identification systems  15   a , passing by a portal  16 ,  26  may cause the proximity of the target  35  to be detected, read, and reported. Likewise, if a shirt  48   f  operates as a securement  48 , then a pass  35  or target  35  may be in a pocket, or secured to the shirt  48   f . A wristband  48   c  may contain a target  35  easily presentable to a reader  15  at a fixed location at about waist height or above. For example, a user  45  may orient the wristband  48   c  and target  35  associated therewith near the sensor  37  of any reader  15  in order to provide identification, location, and time to the master controller  40 . 
         [0085]    The ankle band  48   d  illustrated may be well adapted to radio frequency detectors  37   a , and certain bar code readers  15   c . For example, if a reader  15  is positioned in a comparatively low position close to a deck  14 ,  24 , then passage of a user  45  thereby will result in detection of the target  35  on the band  48   d . Moreover, if feet must pass through a gate, they present ready orientation and comparatively restrictive distance with respect to a deck  14 ,  24  and reader  37 . 
         [0086]    Similarly, a belt  48   e  of a harness  46  may have attached thereto a target  35 . Somewhat more cooperation from a user  45  may be required in order to assure that no arm, equipment, or other obstruction is between the target  35  and any individual sensor (reader)  37  needing to “view” that target  35 . Nevertheless, such a location is unlikely to be damaged, obscured, or accidentally unavailable. Here again, convenience of the user  45  is one consideration. Nevertheless, a user  45  will be motivated to properly present a target  35  to a reader  15 , inasmuch as the system  10  will not function until the reader  15  has received confirmation that a target  35  has arrived, indicating that the corresponding user  45  is in the correct place. 
         [0087]    Similarly, a lanyard  48   b  may connect to a target  35  worn around the neck. One advantage of a lanyard  48   b  is that a user  45  may grip the target  35  on the lanyard  48   b  and present that target  35  to a particular sensor, of virtually any type. For another example, a reader  15   e  that provides a key pad  37   e  as the detector  37 , may be served well by the presence of all key information being on the target  35  or pass  35  attached to the lanyard  48   b . Similarly, various readers  15  may be presented (by the user  45 ) with the target  35  on the lanyard  48   b  from a variety of angles. Again, the size of the lanyard  48   b  may be selected to accommodate such access by readers  15 . 
         [0088]    As a practical matter, it has been official, indeed almost essential, that a user  45  receive feedback from a reader  15 . For example, a user  45  or rider  45  needs to know from the reader  15  that a target  35  has been read, and has been accepted. Thus, for example, a sound, light, voice, image, text, or the like may be presented to a user  45  on a monitor screen  39  available on any reader  15 . Thus, LED (light-emitting diode) lights, sounds, bells, alarms, voices, and the like may be provided as a monitor  39  on any reader  15  providing feedback to a user  45 . 
         [0089]    Just as a wristband  48   c  or ankle band  48   d  may provide a ready location and position for holding a target  35 , so an arm band  48   a  may provide a proper securement  48  for a target  35 . Of course, a user  45  may simply carry a target  35  or a pass  35  in the hand as well. Again, this may be interpreted as one variation of the lanyard  48   b  solution. If a user  45  is going to hold a target  35  or a pass  35  in a hand, then perhaps that hand should be permitted to simply release the target  35 , and have a lanyard  48   b  or other tethering mechanism retrieve and secure that pass  35  for the next use. 
         [0090]    In some respects, a pass  35  that is held in the hand provides for precision required by electronic equipment in various types of readers  15 . Thus, any proximity sensor  37   f , or any detailed data reader, such as magnetic card readers  37   b , bar code readers  37   c , or the like need not rely on automatic detection of a user  45 , but an affirmative presentation by a user  45  of a pass  35  or target  35  for reading. 
         [0091]    Referring to  FIGS. 4 and 5 , while continuing to refer generally to  FIGS. 1 through 18 , a trolley  50  may be configured in any one of the manners illustrated in the references identified hereinabove as incorporated herein by reference. Various trolleys  50  are illustrated therein, and described in great detail. In a system  10  in accordance with the invention, an arm  52  or lever  52  may operate as the frame  52  of the trolley  50 . 
         [0092]    To the lever  52  or arm  52  may be secured a hanger  54  movable therealong. The hanger  54  will typically operate as a slide  54  (on rollers or not) that can move along the arm  52 . In one presently preferred embodiment, the hanger  54  is free to move along the arm  52 , in accordance with control by a user  45 . That is, a user  45 , suspended in a harness  46  from a sling  55  or other attachment mechanism  55  may be able to pull on a tether  56  attached to a handle  57 . For example, the tether  56  draws the hanger  54  along the arm  52 , away from the extreme end thereof. In this way, the position of the effective weight of a user  45  transferred through the sling  55  to the hanger  54  changes the braking of the trolley  50 . 
         [0093]    In selected embodiments, the hanger  54  may be pinned at a specific location along the arm  52 . For example, if a child is the rider, or if a user  45  does not desire to exercise braking control on the trolley  50 , then the arm  52  may be fixed at a particular effective leverage, by positioning the hanger  54  at a specific location along the arm  52 . This results in a constant braking force due to a fixed lever arm or lever advantage. Leverage exists between the hanger  52  on one end and the brake  58  on the other end. These pivot with about the bracket  60  or frame  60  about the axle  72  or pin  72  under the roller  62  or wheel  62  that rolls along the track line  20 . 
         [0094]    For example, in various embodiments illustrated in the references incorporated herein by reference, single-or multi-wheel  62  embodiments are described. Accordingly, a selected number of rollers  62  mounted in a frame  60  permit the trolley  50  to roll along the track line  20 . The leverage of the arm  52 , and specifically the weight of a user  45  suspended from the hanger  54  by a sling  55  or other securement  55  provides leverage about the fulcrum that is the roller  62  in the frame  60 . 
         [0095]    The brake system  58  provides frictional braking against the track line  20  by the brake  58  according to the force applied the hanger  54  by a user  45 . Thus, one may see that as described in the references incorporated herein by reference, the hanger  54 , if mobile along the arm  52 , may be drawn by the tether  56  to move the effective lever arm (change the leverage advantage) of a user  45  or the weight of a user  45 . This multiplied force is effectively applied as the normal force in applying friction by the brake  58 , where friction drag force is a constant multiplied by the normal force. 
         [0096]    Various types of harness  46  may be suitable. For example, the harness  46   a  is a climbing harness typically used in rock climbing, rappelling, and in some inspection, and other servicing of items at heights that may be dangerous to a user  45 . For example, whether working on a roof, a tower, a track line  20 , a ski lift, or the like, a climbing harness  46   a  may be donned by a user  45 . 
         [0097]    A seat  46  or harness  46  may be configured as a climbing harness  46   a . It has a belt  63   a  as well as leg loops  63   b  in this example. The leg loops  63   b  are connected by a lateral tie  63   c  extending therebetween and sewn together carefully by certified methods in order to assure an ability to provide lifesaving strength in the event of a fall. Meanwhile, a vertical tie  63   d  connects the lateral tie to the belt  63   a . Typically, a link  63   e  such as a carabiner  63   e  will connect a sling  63   f  (such as sling  55 ) between the link  63   e  and a link  63   g  connecting to the hanger  54 . 
         [0098]    In an alternative embodiment, a harness  46  may be configured more like a chair  46  having a seat  64   a  suspended from vertical risers  64   b . Likewise, the seat  64   a  may continue to a seat back  64   c . Meanwhile, various reinforcement straps  64   d  may provide substantial additional support for the harness  46   b . In this way, for example, the seat  64   a  and seat back  64   c  provide comfort, but the maximum safety support in case of emergency is provided by the main straps  64   d  of the harness  46   b.    
         [0099]    A spreader bar  65  may provide for comfort, ease of mounting and dismounting the harness  46   b , and the like. Again, spreader bars  65  have been discussed in great detail in the patent documents incorporated herein by reference. Significantly, the spreader bar  65  may replace all or part of the length of a sling  55 . Alternatively, a spreader bar  65  may be suspended from a sling  55 . 
         [0100]    At an upper end of a track line  20 , above the deck  14  of the upper station  12 , the launch block  32  provides registration of the trolley  50 . In the illustrated embodiment, the trolley  50  includes the main roller  62  supporting it and a caboose  58  providing braking. 
         [0101]    Referring to  FIG. 5 , a trolley  50  may fit part of its caboose  58  within a launch block  32 . By fitting the entire width  102  of the caboose  58  or brake system  58  within the launch block  32  various registration interlock functions are enabled. A width  102  or thickness  102  of the caboose  58  needs to fit in the launch block  32 . The height of the caboose  58  needs clearance for motion up and down. 
         [0102]    The brake system  58  or caboose  58  has a thickness  102  that fits within a receiver  81  formed in the launch block  32  in order to register spatially and engage for interlocking. 
         [0103]    To remove and install the trolley  50  on a track line  20 , the swing arm  61  or gate  61  must be cleared of the pin  72  that operates as the pivot  72  about which the lever arm  52  is supported and tilts. Typically, a swing arm  61  pivots about an axle  67  of itself and of the wheels  62 , once the pivot pin  72  of the arm  52  has been lifted sufficiently high to release out of the slot  71   a . By lifting the lever arm  52 , the pin  72  or axle  72  is lifted within the slot  71   a . Meanwhile, the pin  72  also lifts in the slot  71   b  in the frame  60  or housing  60  opposite the swing arm  61  of the frame  60 . The slot  71   a , having an “L” shape, will not release the pin  72 , until the pin  72  rises in the slot  71   a . Thereafter, since the slot  71   b  cannot move, longitudinally along the direction of the lever arm  52 , with respect to the pin  72 , the swing arm  61  must swing forward, thereby releasing out the pin  72  to exit the opening of the slot  71   a.    
         [0104]    Thereafter, the opening of the swing arm  61  by pivoting it in a forward direction with respect to the axle  67 , provides access to the track line  20  supporting the roller  62  or pulley  62 . However, the removal of the trolley  50  from the track line  20  requires removing the roller  62  from riding on the track line  20 . Thus, the brake system  58  must also open. 
         [0105]    To remove the trolley  50  therefore requires that the top cage  75  of the caboose  58  be flipped open to release the track line  20  captured therewithin. 
         [0106]    The caboose  58  will be described in more detail hereinbelow. However, suffice it to say that the caboose  58  includes a base  77  or frame  77 . The frame  77  holds an axle  96  that secures the top cage  75 , pivotally linked to the frame  77 . An interlock system  74  provides securement and selective release of the top cage  75  to pivot about its axle  96 . Pivoted into an open position, the top cage  75  exposes the track line  20  therewithin, thus permitting removal of the trolley  50  from the track line  20 . 
         [0107]    Referring to  FIGS. 4, 5, and 9B , one will notice a snap shackle  69   a . The snap shackle  69   a  may fit about the pin  72  captured within the snap shackle  69   a . In general, a release mechanism may be configured in any number of ways. In one embodiment, a snap shackle  69   a  may include a catch  69   b  that is captured by a pin  69   c . The snap shackle  69   a  may be mounted on a cable, or an arm  64   d.    
         [0108]    The arm  64   d  is secured to the launch block  32 . The catch  69   b  of the snap shackle  69   a  engages the pin  72  that acts as an axle  72  for the lever arm  52 . The arm  64   d  and snap shackle  69   a  act as a gauge to measure and prove a distance between the launch block  32  and the pin  72 . Thus, the caboose  58  must properly fit within the launch block  32  for the pin  72  to be close enough to fit within the catch  69   b  of the snap shackle  69   a . Other attachment schemes and latches or catches are discussed hereinbelow. 
         [0109]    In the illustrated embodiment, withdrawing a pin  64   c  extending into the extreme end of the catch  69   b , releases the catch  69   b  to pivot away, thus releasing the pin  72  and the trolley  50  from engagement with the launch block  32 . 
         [0110]    Referring to  FIGS. 6A through 6C, 7, and 8A through 8F , while continuing to refer generally to  FIGS. 1 through 18 , a caboose  58 , or brake system  58 , may include various components. For example, the brake system  58  or caboose  58  may include a pad  59  mounted within. Typically, the caboose  58  is spaced some distance away from the frame  60  for the roller  62  or main wheel  62 . Typically, the brake system  58  is fixed in effective rigid body motion with respect to the lever arm  52 . In fact, the lever arm  52  may fit within side plates  94  forming a frame  94  of the caboose  58 . 
         [0111]    In the illustrated embodiment, the top cage  75  is pivotable with respect to the frame  77  formed by the side plates  94 . A significant feature of the caboose  58  is an interlock system  74 . For example, the top cage  75  is provided with a slide lock  76 . The slide lock  76  actually represents sliding of the entire top cage  75  with respect to the frame  77 . The slide lock  76  fits into a relief region  78  on the frame  77 . 
         [0112]    Typically, the relief region  78  includes a main seat region  79   a  and an interlock region  79   b . The slide lock  76  initially pivots about the axle  96  down with the top cage  75 , until the slide lock  76  fits into the main seat  79   a . Then, the extreme end of the “L”-shaped slide lock  76  moves rearward into the interlock seat  79   b  or interlock space  79   b . This action requires that the entire top cage  75  and slide lock  76  slide backward or rearward along the axle  96  to fit the slide lock  76  into the interlock region  79   b  of the relief region  78 . This places the distal end of the slide lock  76  under a keeper  79   c  restricting the top cage  75  from pivoting out of position. Thus, the top cage  75  and slide lock  76  pivot in rigid body motion together until the slide lock  76  is in the relief region  78 , seated in the main seat  79   b . After sliding backwards, the top cage  75  and slide lock  76  secure the distal end of the slide lock  76  under the keeper  79   c  in the interlock seat  79   b.    
         [0113]    Once the slide lock  76  has pivoted and slid properly into a locked position, an interlock  80  or dog  80  pivots down into the relief region  78  blocking the slide lock  76  from sliding back out. The interlock  80  may be spring loaded, biased, or simply operate by gravity. However, the interlock  80  not only interlocks with the slide lock  76 , to keep the slide lock  76  in place, but operates as a barrier to entry of the caboose  58  into the receiver  81  of the launch block  32 . 
         [0114]    If the interlock  80  cannot fit down into the relief region  78 , in a portion of the main seat  79   a , then the slide lock  76  is not in the proper, closed position. Once the slide lock  76  is in the proper, closed position, the interlock  80  may fit down into the relief region  78 . Thus, the extension at the end of the interlock  80  is properly positioned to fit within a slot  103  formed in the launch block  32  for exactly that purpose. Thus, the interlock  80  operates not only as an interlock  80  for the slide lock  76 , but also for the entire caboose  58  fitting into the launch block  32 . 
         [0115]    After entering the opening  81 , targets  82  on the back surface or rearmost surface of the caboose  58  are detected by sensors  83 , such as proximity sensors  83 . Meanwhile, a detent  84  or latch system  84  locks the caboose  58  into the launch block  32 . For example, an actuator  85 , such as a solenoid  85  may operate activating surfaces  86  in order to engage the contacts  87   a ,  87   b  between the frame  77  of the caboose  58 , and the launch block  32 . 
         [0116]    The detent  84  may have a spring  88  provided by a spring force favoring engagement. Thus, the actuator  85  may withdraw the detent  84  only upon receiving the proper signal of control (e.g., from the controller  40 ) and the power required to operate the actuator  85  to withdraw the detent  84 . Typically, the registration face  89  on the launch block  32  will fit against the detent  84 . 
         [0117]    In various embodiments, an actuator  90  or trigger  90  may operate to withdraw the detent  84  from contact  87   a ,  87   b  between the detent  84  and the frame  77  of the caboose  58 . 
         [0118]    The caboose  58  may be secured by various fasteners  91  or bolts  91 . Some may serve as dual purpose fasteners  91 , such as the axle  91   a . Each of these fasteners  91  may be secured by a keeper  92  or threaded directly into one of the side plates  94 . Spacers  93  may maintain a distance between the side plates  94 . Meanwhile, the brake shoe  59  or pad  59  also serves as a spacer  93  between the side plates  94 . 
         [0119]    The pad  59  and the top cage  75  are shaped to provide a way  95  or passage  95  sized to receive the track line  20 . To fit the track line  20  into the way  95 , the swing arm  61  must be removed from the pin  72 , and rotated forward. Meanwhile, the top cage  75  must slide forward along its axle  96  until the clearance  97  has been taken up. By sliding, the slide lock  76  is freed from the constraint of the keeper  79   c . Once free, pivoting of the slide lock  76  with the top cage  75  removes it from the relief region  78 . Thus, as the top cage  75  pivots about its axle  96 , the way  95  has been opened to release the track line  20  from capture therewithin. 
         [0120]    The caboose  58  may include a hanger  98  having an aperture  99  therein for receiving a fastener  63   e , such as a carabiner  63   e  for a belay line. This line is a second level of protection in case of a failure of another component of the system  10 . 
         [0121]    For example, typically, the hanger  54  supports a sling  55  and harness  46 . Meanwhile, the harness  46  on a rider  45  is also secured by a belay line (e.g., another sling  55 ) to the hanger  98  as an emergency precaution. Thus, the brake system  58  operates as an additional support capable of supporting a rider  45  on the track line  20 . This support operates in even the most extreme condition of having the hanger  54  fail, or following a failure of the pin  72 , the lever arm  52 , the main frame  60  or the like. 
         [0122]    Referring to  FIGS. 8A through 8F , while continuing to refer generally to  FIGS. 1 through 18 , the interlock  80  may alternatively be configured as a spring-loaded or an elastically deflecting interlock  80 . In this embodiment, the interlock  80  is formed to spring out away from the relief region  78 . Meanwhile, a button  101  extends above the surface of the remainder of the interlock  80 . 
         [0123]    In this embodiment, the slide lock  76  pivots into place, under force, thereby depressing the button  101  and deflecting the interlock  80 . Once the slide lock  76  has depressed the button  101 , and entered fully into the relief region  78 , the slide lock  76  is in a position to slide rearward under the keeper  79   c.    
         [0124]    As the slide lock  76  slides with the top cage  75  rearward, the slide lock  75  fits under the keeper  79   c . Once clear of the interlock  80 , the slide lock  76  passes off and releases the button  101 , permitting the interlock  80  to spring back out. Once in the outer or unstressed position, the interlock  80  obstructs and prevents the slide lock  75  from moving forward out from under the keeper  79   c . The button  101  then protrudes to interfere, and thereby acts as a restraint against motion of the slide lock  76  in a forward direction. Thus, the top cage  75  is prevented from moving forward and out of a locked position. 
         [0125]    The slide lock  76  may be released by depressing the button  101 , thus deflecting the interlock  80  sufficiently to permit the slide lock  76  to slide forward with the top cage  75 . Once forward, and completely clear of the keeper  79   c , the slide lock  76  may pivot up with the top cage  75  about the axle  96  to an open position. 
         [0126]    Referring to  FIGS. 9A through 9C , while continuing to refer generally to  FIGS. 1 through 18 , various alternative mechanisms may exist for securing the caboose  58  within the launch block  32 . For example, some portion of the frame  77  may fit within the launch block  32 . A latch  84  or detent  84  may be operated by an actuator  85 , such as a solenoid  85 . Typically, the latch  84  may have a spring  88  or spring portion  88  that biases the latch  84  into engagement with the frame  77 . For example, registration surfaces  89   a ,  89   b  may engage to capture the frame  77  by the latch  84  of the launch block  32 . Upon operation of the actuator  85 , the spring  88  may be overcome, withdrawing the latch  84  from engagement with the frame  77 . 
         [0127]    Engagement may occur by contact between the contact surfaces  87   a ,  87   b . The contact surfaces  87   a ,  87   b  may first come into contact by relative motion (linear translation) between the frame  77  and the latch  84  of the launch block  32 . The contact surfaces  87   a ,  87   b  engage, thus driving the latch  84  away from the frame  77 . Eventually, upon coming to a proper registration position, the surfaces  89   a ,  89   b  pass one another, clearing for engagement. At this point, the spring  88  biases the latch  84  to slide into engagement with the frame  77 . Again, the actuator  85  may overcome the bias of the spring  88 , and withdraw the latch  84 , thus removing the surfaces  89   a ,  89   b  from engagement with one another. 
         [0128]    Setting the trolley  50  on a track line  20  is typically a matter of opening a frame  60  and a brake system  58  (caboose  58 ). The frame  60  is typically opened by rotating a swing  61  or swing arm  61  about an axle  67  or pivot point  67  to provide an opening within the frame  60  into which the track line  20  may pass. In reality, it is the frame  60  that moves into a position around the track line  20 . The track line  20  does not typically move. 
         [0129]    Rather, the trolley  50  is lifted to the track line  20 , with the swing arm  61  open in the frame  60 . Thereby, the wheel  62  or roller  62  is engaged on the track line  20 . Upon engagement of the track line  20  by the wheel  62 , the swing arm  61  may be rotated or pivoted downward and rearward (where rearward is with respect to the ultimate direction of travel of the trolley  50 ). Thus, the track line  20  is captured within the frame  60 , by the swing arm  61 . In certain embodiments, the swing arm  61  may be provided with a slot that is ‘L’ shaped. 
         [0130]    The slots  71   a ,  71   b  permit the swing arm  61  to receive a pin  72  fixed to the frame  60 . The pin  72  moves into the foot of the ‘L,’ where the ‘L’ is actually upside down and backwards. In other words, the ‘L’ is flipped downward, or the leg of the ‘L’ flips down in rotation about the foot of the ‘L’ as an axis. Thus, the pin  72  passes into the rear side of the slot  71 , as the swing arm  61  rotates downward and rearward. 
         [0131]    Once the trolley  50  is supported on the track line  20  by the wheel  62  or roller  62 , sometimes called a pulley  62 , the frame  60  supports the entire trolley  50  on the track line  20 , and the pin  72  drops in the slot  71   a . For example, the lever arm  52 , by virtue of its weight, drops down along the leg of the slot  71 , thus capturing the swing arm  61  against any further movement. In this position, the swing arm  61  and the remainder of the frame  60  completely surround the wheel  62 , the track line  20  captured therebelow, and secured to the lever arm  52 . At this point, the trolley  50  is secure and non-removable. 
         [0132]    With support on both sides of the frame  60 , by virtue of the frame  60  and swing arm  61  securing to the pin  72 , the trolley  50  may be considerably lighter than other configurations. That is, no open frame nor cantilevered support is required. Since the pin  72  operates as an axle  72  for the pivoting of the lever arm  52 , the frame  60  including its swing arm  61  provide adequate, secure, lightweight support for the trolley  50  on the track line  20 . 
         [0133]    Setting the trolley  50  on the track line  20  typically involves opening the swing arm  61 , as well as opening the brake system  58  or caboose  58 . The swing arm  61  rotates forward about its axle  67  after the lever arm  52  has been lifted in the slots  71   a ,  71   b  formed in the frame  60  and swing arm  61 . The slot  71   b  on the solid portion of the frame  60  is straight. The slot  71   a  on the swing arm  61  is L-shaped. 
         [0134]    Thus, to set a trolley  50  on a track line  20 , it is necessary to open the frame  60  by swinging the swing arm  61  forward about its axle  67 . It is likewise necessary to open up the brake system  58  or caboose  58  by releasing the interlock  74  thereof, thus releasing one side of the brake system  58  or caboose  58  to rotate or pivot away from the swing arm  61 . 
         [0135]    Once the swing arm  61  swings forward to open, and the top cage  75  of the caboose  58  or brake system  58  has been pivoted away from the swing arm  61 , the track line  20  fits under the wheel  62  in the frame  60 , and passes over the brake pad  59  of the brake system  58 . The forces applied by the wheel  62  and brake pad  59  create a “couple” (offset, opposing forces producing a movement or torque) as understood in engineering statics. 
         [0136]    Closing the trolley  50  on the track line  20  involves rotating swing arm  61  circumferentially or arcuately downward and rearward to engage the pin  72  in the slot  71   a.    
         [0137]    The top cage  75  or closure  75  of the caboose  58  or brake system  58  may be pivoted across, toward the swing arm  61 , to pass over the top of the track line  20 . Thus, the closure  75  of brake system  58  or caboose  58  does not actually ride or continually contact the track line  20 . Rather, the lever arm  52  tends to decline or drop, lifting the brake system  58  until the pad  59  contacts the bottom side of the track line  20 . 
         [0138]    In this position, the weight of a rider  45  suspended from the hanger  54  on the lever arm  52  by the sling  55  provides weight (e.g., force) on the lever arm  52 , pivoting about the pin  72 . The pin  72  or axle  72 , acting as a fulcrum  72 , elevates the brake system  58 , applying leveraged force of the pad  59  against the bottom side of the track line  20 . 
         [0139]    The actual weight of a rider  45  suspended in a harness  46  on the tether  56  from the slide  54  provides the actual braking force. The details of operation of such a trolley  50  are described further and illustrated in the references incorporated herein by reference. 
         [0140]    For example, the interlock system  74  includes a top cage  75  provided with a slide lock  76 . The top cage  75  pivots toward the swing arm  61 , and toward the track line  20  positioning the slide lock  76  within the frame block  77 . The frame block  77  provides a substantial part of the support for the pad  59  in the braking system  58 . The frame block  77  may be called a caboose block  77 , since it forms the principal structure  77  or supporting structure  77  for the caboose  58 . 
         [0141]    The caboose block  77  or frame block  77  is provided with a relief portion  78  fitted to the slide lock  76 . Thus, after the top cage  75  has been closed, the slide lock  76  comes into the relief  78  or fits into the relief  78  of the caboose block  77 . The relief  78  includes both a main seat  79   a , into which the slide lock  76  fits, and interlock seat  79   b  into which the foot of the slide lock  76 , or a bottom most portion thereof may slide. Thus, the slide lock  76  fits into the relief region  78  extending below the outer surface of the frame block  77  or caboose block  77 . 
         [0142]    Thereafter, the rider  45  slides the slide lock  76  rearward (with respect to the direction of motion that the trolley  50  will eventually take) thus sliding the slide lock  76  under a keeper  79   c . In this position, the slide lock  76  can no longer pivot out of the relief region  78 . Moreover, the entire top cage  76  is now locked against the frame block  77  or caboose block  77 . Meanwhile, another interlock  80  (dog  80 ) pivots down to drop into the relief region  78  just forward of the slide lock  76  in its rear-most position. Thus, the slide lock  76  is now trapped under the keeper  79   c , unable to move forward in the relief region  78 . 
         [0143]    That is, the interlock  80  has dropped into the main seat  79   a  ahead of the slide lock  76  or in front of the slide lock  76 . Thus, the interlock  80  or safety dog  80  has now interlocked the slide lock  76  into place, while the keeper  79   c  provides the force of a fixed relationship to the main seat  79   a  of the relief region  78 . This arrangement fixes the slide lock  76  against any relative motion with respect to the frame block  77  or caboose block  77 . 
         [0144]    In the illustrated embodiment, the caboose block  77  may include various structural components, fasteners, and the like. In the illustrated embodiment, the caboose block  77  will fit substantially in its entirety, or at least its entire width, inside the launch block  32 . 
         [0145]    Also, for example, a launch block  32  may include an opening  81  or receiver  81  sized to fit the width of the entire caboose block  77  or frame block  77 . Meanwhile, the caboose block  77  is provided with one or more targets  82  that are metallic, and specifically contain substantial iron. These targets  82  will be detected by sensors  83  such as proximity sensors  83  in the launch block  32 . The rider  45  rolls the trolley  50  backward or rearward along the track line  20  to fit the caboose block  77  inside the receiver  81  of the launch block  32 . The launch block  32  includes a detent, which may be a bar  84 , a latch  84 , or the like operated by an actuator  85  such as a solenoid  85 . 
         [0146]    Thus, an activating surface, typically associated with a protrusion  86  having a slope associated with it, or angle, will contact the detent  84 , pushing the detent  84  some distance out of its equilibrium position. Upon reaching a contact surface  87   a  on the detent  84  by a contact surface on the caboose block  77 , the detent  84  automatically moves into engagement, placing the contact surfaces  87   a ,  87   b  in contact with one another. Due to a spring  88  applying a bias force to the detent  84 , the activating surface  86  effectively comes to an end at the contact surface  87   b.    
         [0147]    At that point, the contact surfaces  87   a ,  87   b  slide into engagement, urged by the spring  88  pushing the detent  84 . Typically, the contact surfaces  87   a ,  87   b  are engaged when the targets  82  approach a registration face  89  on the launch block  32 . Thus, the sensors  83  approach the registration face  89 , typically making contact at about the same time or position that the contact surfaces  87   a ,  87   b  engage with one another. 
         [0148]    Typically, the registration face  89  will represent a physical bumper position, and the targets  82  may actually be recessed slightly. Typically, targets  82  will be set away from the proximity sensors  83  a distance of from about one to about three millimeters. Thus, actual contact will typically not occur between the targets  82  and the sensors  83 . Instead, the registration face  89  will contact the caboose block  77  with sufficient clearance to permit engagement by the contact surfaces  87   a ,  87   b.    
         [0149]    The proximity sensors  83  are thus engaged or activated to report once a user  45  has set  204  the detent  84  or lock  84 . An audible click may be heard, and the trolley  50  will be secured to the launch block  32  by engagement between the launch block  32  and the caboose block  77 . 
         [0150]    Setting the lock  84  may be tested  205  both by physical observation that the trolley  50  is locked into the launch block  32 , as well as by lights, or the like verifying that the caboose block  77  is secured within the launch block  32 . Typically, reporting  206  or enabling  206  involves detection  206  indicating to the master controller  40  and other intervening devices, that the proximity sensors  83  are in sufficiently close proximity to the targets  82 , thus indicating a proper positioning of the caboose block  77  of the trolley  50  with respect to the launch block  32 . 
         [0151]    An actuator  90  may actually be thought of as a trigger  90  that will release the caboose block  77  from the launch block  32 . Once free, the caboose block  77 , fixed to the trolley  50 , will descend along the track line  20 . However, the departure process may involve numerous safety mechanisms or interlocking devices and procedures. 
         [0152]    The interlock system  74  includes a largely mechanical interlocking of the top cage  75 , by the slide lock  76  securing the top cage  75  with respect to the caboose block  77 . Meanwhile, if the slide lock  76  does not fit down into the relief region  78 , then the caboose block  77  will not fit within the receiver  81  of the launch block  32 . By the same token, if the slide lock  76  has not slid sufficiently rearward to permit the safety dog  80  or mechanical interlock  80  to fit down in front of the slide lock  76  in the main seat  79   a  of the relief region  78 , then the safety dog  80  extends too far away from the outer perimeter of the caboose block  77 . In this event, the caboose block  77  will not fit within the receiver  81 . 
         [0153]    As a practical matter, because the brake pad  59  may eventually wear, the brake system  58  or caboose  58  may eventually pivot, and rise with respect to the track line  20 . Thus, space to accommodate vertical motion of the caboose  58  or brake system  58  within the receiver  81  is provided. However, clearance from side to side is sufficiently close between the caboose  58 , and particularly the caboose block  77  and the side walls of the receiver  81 , that only a properly closed and secured top cage  75  will be permitted to pass into the receiver  81 . Thus, mechanical interlocks provide safety. 
         [0154]    Triggering by a user  45  typically involves mechanical release of a release link  108  or the like. Meanwhile, triggering also involves release from the launch block  32 . 
         [0155]    For example, a release link  108  has a highly leveraged securement loop  69   a  in which a comparatively modest, virtually unloaded (without force), bracket  69   a  is secured about the catch  69   b . Thus, the snap shackle loop  69   a  provides significant leverage advantage for the rider  45 . Upon release of the pin  69   c , by a rider  45 , the snap shackle loop  69   a  is free to open. The comparatively small size and weight of the actuator element  69   d  causes the actuator element  69   d  to pivot, thereby releasing the catch  69   b.    
         [0156]    That is, the snap shackle loop  69   a  releases the catch  69   b , as the actuator  69   d  moves out of engagement. Thus, the pivoting nature and the variable curvature of the actuator  69   d  provide a tremendous leverage advantage. This amounts to an effectively unloaded engagement between the pin  69   c  and the actuator  69   d . Thus, a comparatively high load may be secured by the snap shackle loop  69   a  against the catch  69   b . Yet, release requires very little force. Almost no frictional binding exists against the pin  69   c  in the actuator  69   d . Thus, removal of the pin  69   c  easily releases the actuator  69   d , which then has only its own weight to be moved by the force of the catch  69   b  against it. 
         [0157]    Removing the trolley  50  involves releasing the entire top cage  75  of the caboose  58  in order to permit removal thereof from the track line  20 . Similarly, the swing arm  61  is drawn down (e.g., moving the catch  6   b  up). The swing arm  61  may now be pivoted about the axle  67  away from the catch  69   b . Thus, the engagement of the catch  69   b  by the swing arm  61  is removed. 
         [0158]    The swing arm  61  swings forward, away from the caboose  58 , thereby clearing an opening for the main roller  62  or wheel  62  (sheave  62 ) to be lifted off the track line  20 . Thus, with the top cage  75  also open (pivoted up and away from the main block  77  or frame  77  of the brake system  58 ), the trolley  50  may simply be lifted away from the track line  20 . 
         [0159]    Following removal  228  of the trolley  50 , the trolley  50  may be tucked into a backpack, fitted into a sling or carrier suspended from the shoulder of a user  45 , or the like. 
         [0160]    Registering with the launch block  32 , a trolley  50  may have a mechanical interlock in the various components  79  and the interlock safety dog  80  that must mechanically fit into a receiving region  81 . Proximity sensors  83  may detect a failure to register the trolley  50 , and particularly the caboose  58 , in the launch block  32 . 
         [0161]    However, the safety dog  80  must clear or fit into its designated opening in the launch block  32 . Also, the gauge length required for the snap shackle  69   a  to engage a catch  69   b  is a mechanical distance that must be met. It corresponds with drawing the trolley  50  within the launch block  32  a sufficient distance to provide detection of targets  82  by the proximity sensors  83 . 
         [0162]    Meanwhile, the proper positioning of a detent  84  that must be physically moved by an actuator, such as a solenoid, or the like may provide an electrical or electronic mechanism for detecting whether a trolley  50  is properly registered in a launch block  32 . 
         [0163]    Referring to  FIG. 10 , while referring generally to  FIGS. 1 through 18 , and particularly to  FIGS. 14 through 18 , a system  10  in accordance with the invention will typically involve one or more track lines  20  extending between an upper location and a lower location. Typically, track lines  20  may be suspended between towers, other man-made structures, or natural structures, such as trees. A track line  20  will typically suspend as a catenary, a term of art known in engineering, and used here in its common, ordinary, engineering meaning. 
         [0164]    Track lines  20  may be suspended to run in multiple parallel paths. They may also be suspended in multiple legs of a longer tour. Typically, each leg has a beginning and end. Ends of adjacent legs of such a tour may be in proximity to one another permitting ready access therebetween by riders, but also providing the freedom to dismount from a track line  20  and hike, relax, observe, or wander before continuing on the next leg of the tour. 
         [0165]    In the illustrated embodiments, riders  45  may be tracked by means of a target  35  associated with the rider  45 , with the rider&#39;s harness  46 , or with a trolley  50  that supports the user or rider  45  in a harness  46 , traveling along the track lien  20 . Typically, a harness  46  containing a rider  45  is connected by a link  49 , such as a carabiner secured between the harness  46  and the trolley  50 . 
         [0166]    Again, harness  46  is a word well understood in the arts of climbing, mountaineering, “high angle” work, working high above the surface of the earth, such as suspending over the sides of buildings, military operations, search and rescue, and so forth. Harnesses  46  are also described in some detail in the references hereinabove cited and incorporated by reference. In the illustrated embodiment, multiple trolleys  50  are used. 
         [0167]    A trolley  50   a  contains a lever arm  52 . Along that lever arm  52  a slide  54  may move. Typically, the slide  54  may actually have rollers or bearings that travel along a top surface of the lever arm  52 . In this way, the slide  54  is quite free to move with a minimum of frictional resistance along the lever arm  52 . Because the lever arm  52  is free to pivot about the axle  91   b  with respect to the track line  20 , the lever arm  52  forces the pad  59  of a brake system  58  to engage frictionally against a lower side or surface of the track line  20 . 
         [0168]    Because the slide  54  is comparatively free to move along the lever arm  52 , a rider  45  may suspend in a harness  46  from the trolley  50   a . Meanwhile, a system of carabiners  49  and slings  55 , such as the sling  55   a , will suspend a harness  46  with a rider  45  seated or otherwise supported therein. 
         [0169]    By means of a tether  56 , effectively a small diameter cable  56 , a rider  45  may pull on a handle  57 , thus drawing along the lever arm  52  the slide  54 , which is connected to the other end of the tether  56 . A user  45  exerting no force on the handle  57  is effectively supported exclusively by the harness  46 , sling  55   a , and a connecting link  49 , such as a carabiner  49 , to the trolley  50   a . Accordingly, the slide  54  when free from force by a user  45 , with no force being exerted on the handle  57  and tether  56 , tends to depress the lever arm  52 , and thus slide forward along the lever arm  52 , increasing the leverage advantage of the weight of the user applied to the slide  54  by moving away from the axle  91   b.    
         [0170]    For example, as the slide  54  moves toward the front end of the lever arm  52 , the leverage that the weight of a user applies to the brake system  58  is increased. One can see that the brake system  58  pivots to a position exerting force and pressure by the pad  59  against the track line  20  as the lever arm  52  pivots about an axle  91   b  or bolt  91   b  under the influence of the weight of a rider on the hanger  54  or slide  54 . 
         [0171]    Movement downward by the lever arm  52  results in movement upward by the brake system  58 . With force and movement downward by the slide  54  against the lever arm  52 , force and movement upward apply the brake system  58  against the track line  20 . 
         [0172]    A shoe  59  or pad  59  operates to slide along the track line  20 , subject the force of friction. Perhaps more specifically, the pad  59  or shoe  59  applies force against the track line  20 . Meanwhile, the weight of a rider  45  in a harness  46  tends to draw or urge the trolley  50  to roll downward along the decline of the track line  20 . 
         [0173]    According to the rule of frictional engagement (F=μN), the drag force “F” of friction is proportional to the force applied normal (perpendicular) to the surface of the track line  20  by the brake pad  59  or brake shoe  59 . Thus, the resistance “F” or the force “F” resisting movement of the trolley  50  along the decline of the track line  20  is equal to a coefficient of friction μ (a constant, μ, related to the materials of the track line  20  and the pad  59 ) multiplied by the “normal” force “N” (meaning perpendicular load) applied to the contact surface of the track line  20  by the pad  59 . 
         [0174]    In the illustrated embodiment, the wheel  62  or pulley  62  supports the trolley  50  on the line  20 . The wheel  62  may be braked in any of a number of ways. In some embodiments, a mechanical brake pad  59  or shoe  59  operates to provide friction against the track line  20 . In other embodiments, the wheel  62  may be provided with an armature, and the brake system  58  may actually provide eddy current braking or induced current braking. 
         [0175]    For example, the wheel  62  or pulley  62  may resist rolling. To do so, it may act like a motor that is being run in reverse or forced in reverse even though it is rolling or running forward along the line  20 . Thus, the wheel  62  may operate as a motor being forced backward, thereby tending to provide a braking force. 
         [0176]    Alternatively, the pulley  62  may be connected to, or be configured as an armature or stator operating as part of a generator generating a current. The generator may be connected to a load or resistance, which then dissipates the energy, thus providing the mechanical drag for the brake system  58 . Such electromagnetic braking systems may often simply rely on the reverse or the inverse of the operation of motors. 
         [0177]    If the wheel  62  operates as a part of a generator system, then the drag resisting rotation of the wheel  62  is a result of an electrical load connected to the generator system. Direct generation of eddy currents and dissipation thereof may also be relied upon as explained and understood in the electro-mechanical engineering arts. Eddy current braking herein is used in that context and relying on an ordinary engineering definition. 
         [0178]    In another embodiment, braking may be applied to a wheel  62  mechanically. The wheel rolls substantially without slipping along the track line  20 . It may be braked hydraulically, mechanically, or electrically, in order to resist rotation of the wheel  62 . 
         [0179]    One will note that several slings  55  are arranged in the various embodiments illustrated. Typically, a harness  46  contains webbing  64  in important locations. In fact, the harness  46  may look more like a seat  46 , or may be more sparse, with leg loops, waist belt, and so forth as described and illustrated hereinabove. 
         [0180]    For example, in certain embodiments, a harness  46  may involve a chest harness with the leg loops and a waist belt. A harness  46  that includes leg loops, a waist belt, and chest strap or harnessing is a good idea for novices and children. It may be connected to maintain a rider  45  upright without requiring action by the rider  45 . A set of slings  55  interconnected by links  49 , such as carabiners  49 , may connect a harness  46  containing a rider  45  to a slide  54  that operates as a bracket  54  to support the harness  46  by the sling  55  under a trolley  50 . 
         [0181]    One should note that the idler  73  is a roller  73  that does not necessarily engage constantly during travel of a trolley  50  along a track line  20 . Typically, a user  45  relieves the braking force by pulling the handle  57 , thereby releasing pressure by the pad  59  against the track line  20  as described and illustrated hereinabove. Pulling down on the handle  57  draws the tether  56 , connected to the slide  54 . The slide  54  moves backward along the lever arm  52 , changing the leverage advantage of the slide  54  against the brake system  58 . 
         [0182]    In the illustrated embodiments, the brake pad  59  makes a mechanical, frictional, braking action. In other embodiments, either a brake pad  59  may be used, or the wheel  62 , itself, may be braked electromagnetically or otherwise, as discussed hereinabove. 
         [0183]    However, in contrast, the idler  73  rides above the track line  20  without supporting any load, nor even necessarily making contact with the track line  20 . As part of the braking system  58  of the trolley  50 , the idler  73  need only engage if the braking system  58  moves away from the track line  20  sufficiently downward for the idler  73  to be required to restrain the trolley  50  from tilting further. 
         [0184]    The trolley  50  includes various axles  91  supporting the idler  73 , and so forth. In particular, an axle  91   a  supports the idler  73 . The axle  91   b  supports the lever arm  52  pivoting below the main roller  62 . 
         [0185]    Again, a trolley  50   a  may be provided with a lever arm  52 , a brake system  58 , and proper connection systems including carabiners  49 , slings  55 , harness  46 , and so forth. Thus, an individual user may travel down a track line  20  applying the braking force of the brake pad  59  against the track line  20  at will. However, a second trolley  50   b  may also be connected on the line  20  to travel simultaneously with the trolley  50   a . In fact, multiple trolleys  50   b  may connect ahead, behind, or both, with respect to a braked trolley  50   a.    
         [0186]    Referring to  FIG. 11 , the trolley  50   b  may include a hanger  98   b  corresponding to the hanger  98   a  on the trolley  50   a . For the rider of the trolley  50   a , the hanger  98   a  acts as a belay hanger  98   a . That is, the harness  46  of the rider  45  of the trolley  50   a  is suspended from the lever arm  52  by the slide  54  and sling  55   a.    
         [0187]    In contrast, the trolley  50   b  needs no brake. In fact, it should have no brake. Otherwise, coordination and control between the trolleys  50   a ,  50   b  would be difficult, and the risk of impact unsafe. 
         [0188]    For safety, the hanger  98   b  on the trolley  50   b  may be connected to the hanger  98   a  of the trolley  50   a  by a sling  55   f . In general, a harness  46   a  of a rider  45  of the trolley  50   a  may be suspended by a sling  55   a . Meanwhile, a sling  55   e  connects between the harness  46   a  of the rider of the trolley  50   a  and the belay hanger  98   a . Thus, the belay hanger  98   a  operates to provide an additional sling  55   e  in the unlikely event that any failure occurs in the slide  54 , its connecting carabiner  49 , or the sling  55   a . Likewise, should any failure in the arm  52  occur, the rider is still suspended by the trolley  50   a  through the belay hanger  98   a  and sling  55   e.    
         [0189]    Referring to  FIGS. 12 through 14 , and  FIGS. 1 through 18  generally, a rider  45  in a harness  46   b  may be secured to another trolley  50   a  by a sling  55   f . This eliminates the possibility of escape by the trolley  50   b  from the trolley  50   a . Thus, the riders under the trolley  50   a ,  50   b  are linked together by the sling  55   f . Each sling  55   f  also operate as a belay sling  55   f , providing additional connection through a carabiner  49  to the slings  55   f  on the harness  46   b.    
         [0190]    The sling  55   b  may suspend the harness  46   b  of a second rider from a hanger  98   b . Alternatively carabiners may connect these directly without a sling  55 . In the event of a failure of any aspect of the second trolley  50   b , the sling  55   f  provides a suspension of the harness  46   b  from the belay hanger  98   a.    
         [0191]    A bumper  104   b  on the trolley  50   b  may or may not have any equivalent necessary on the trolley  50   a . For example, an unbraked trolley  50   b  does not need the lever arm  52 . The trolley  50   a  may have a bumper  104   a  for contacting the bumper  104   b , if desired, however, 
         [0192]    By whatever mode, a bumper  104   b  on the trolley  50   b  connects to contact the trolley  50   a , thereby minimizing any potential for damage, abrupt contact between metals, or the like. Typically, the bumpers  104  may be formed of rubber, a suitable polymer, or the like. 
         [0193]    Meanwhile, the bumpers  104   b ,  104   c ,  104   d  correspond to the unbraked trolleys  50   b ,  50   c ,  50   d . For example, multiple trolleys  50   a ,  50   b ,  50   c ,  50   d  may operate in tandem at the same time on the same run along the track line  20 . Meanwhile, the brake system  58  on the first trolley  50   a  operates to brake all the trolleys  50 . 
         [0194]    Referring to  FIG. 12 , the three unbraked trolleys  50   b ,  50   c ,  50   d  are bumpered together and against the trolley  50   a , which leads. The braking system  58  of the first trolley  50   a  or lead trolley  50   a  has the effect of controlling (effectively slowing or braking) all the trolleys  50   a ,  50   b ,  50   c ,  50   d.    
         [0195]    Another bumper  104   e  on the front of the lever arm  52  of the trolley  50   a  serves another purpose. This is bumper  104   e  for systems that may attenuate speed at the lower end or landing end of a run along the track line  20 . 
         [0196]    Referring to  FIG. 13 , in yet another embodiment, the trolleys  50   b ,  50   c ,  50   d  may be connected to run ahead of the trolley  50   a . In this embodiment, the slings  55   a ,  55   b ,  55   c ,  55   d  support each of the harnesses  46   a ,  46   b ,  46   c ,  46   d  under their respective trolleys  50   a ,  50   b ,  50   c ,  50   d . Meanwhile, the slings  55   f ,  55   g ,  55   h  connect together the trolleys  50   a ,  50   b ,  50   c ,  50   d . However, here, the trolleys  50   b ,  50   c ,  50   d  do not stack up behind the trolley  50   a , but run ahead of it. Accordingly, they will typically separate by the distance permitted by their interconnections, slings  55   f ,  55   g ,  55   h.    
         [0197]    Regardless, the trolleys  50   a ,  50   b ,  50   c ,  50   d  cannot separate by a great distance. That distance is dictated by the interconnecting slings  55   f ,  55   g ,  55   h . Accordingly, no great variation, or even significant difference, in velocity is obtained or attainable, relatively speaking, between any of the trolleys  50 . Thus the risk of instability or inter-trolley impact is reduced to have virtually no effect. 
         [0198]    Referring to  FIG. 14 , in one embodiment, multiple trolleys  50   b  may be distributed to both trail behind and run ahead of the lead trolley  50   a . One or more may be connected behind, while other trolleys  50   c ,  50   d  may also be connected ahead of the trolley  50   a.    
         [0199]    In some respects, it may easier to operate if all the additional trolleys  50   b ,  50   c ,  50   d  are either in front of or behind. With all unbraked trolleys  50   b ,  50   c ,  50   d  located exclusively either fore or aft, the rider on the trolley  50   a  has a single direction to pay attention to riders. This may be a more secure mode of care with respect to the unbraked trolleys  50   b ,  50   c ,  50   d , with the operator of the braking trolley  50   a  knowing all other riders are either behind or in front. 
         [0200]    It appears that having all riders of unbraked trolleys  50   b ,  50   c ,  50   d  behind the braked trolley  50   a , the controlling rider  45  of the trolley  54   a  is free to look forward upon approaching the end of a particular leg of a track line  20 . On the other hand, with all unbraked trolleys  50   b ,  50   c ,  50   d  ahead of the controlling trolley  50   a , the controlling rider  45  need only look forward at any time to see both the approaching attenuation system and all riders. On the other hand, trolleys  50   b ,  50   c ,  50   d  carrying riders in front of the controlling trolley  50   a  may tend to spread out while descending, but move together upon arriving at an end-of-line attenuation system, as described and shown in the references incorporated hereinabove by reference. 
         [0201]    Referring to  FIG. 15 , a trolley  50  in accordance with the invention may include a front bumper  104 . A rear bumper  105  may be configured for capture of any trailing trolley  50  traveling therebehind. For example, in some embodiments, a rear bumper  105  may include wings  107  in order to pilot a front bumper  104  of a trailing trolley  50  into contact with the impact surface  106  of the rear bumper  105  of the trolley traveling ahead. 
         [0202]    In selected embodiments, the impact surface  106  may actually be slanted in order to urge the arm  52  of a following trolley downward as it moves forward, thus applying braking to the following trolley through its own braking system  58 . Nevertheless, the braking systems  58  of the trolleys  50  are sufficiently robust that a single operator in a leading harness  46  or seat  46  suspended under a leading trolley  50  has sufficient braking power to slow and even stop multiple trolleys  50  following. 
         [0203]    In the illustrated embodiment, the release link  108  may include one or more of the elements  69 . For example, a snap shackle loop  69   a  may capture the eye  270  of a turnbuckle  272 . Meanwhile, a catch  69   b  may secure the loop  69   a  in a closed configuration. Meanwhile, a pin  69   c  may be released by an actuator  69   d  to open the loop  69   a.    
         [0204]    Referring to  FIGS. 16 and 17 , a carrier system  250  may include a structure  252  having some principal function unrelated to a track line  20  and a trolley  50 . For example, it may be the structure  252  of an offshore oil rig, a refinery tower, a gantry at a missile site, a building containing a manufacturing plant for “energetic materials” (an engineering term of art), or the like. 
         [0205]    Connector beams  254  are installed to support the carrier system  250 , and may be secured by any suitable means (e.g., welding, bolts, rivets, pins, clamps, etc.) to the structural beams  256  making up the structure  252 . Vertical pillars  258  and horizontal beams  256  of the structure  252  may be augmented by diagonal bracing, gussets, and so forth according to good structural engineering practice. 
         [0206]    Track lines  20  for egress in emergency situations may be secured to the structure  252 , such as at apertures  262  in flanges  263  of the pillars  258 . Lines  20  may connect through systems such as a clevis  266  and pin  268 , clamps, lugs, and the like, or wrap around bollards or thimbles. Track lines  20  thus descend at some angle  264  dictated by the theory of catenaries  26 . 
         [0207]    In one embodiment of an emergency egress system  10 , a carrier system  250  may be installed on a structure  252  of a facility  253  remote from a safety location. For example, certain manufacturing facilities  253  deal with “energetic materials” such as explosives, combustibles, fuels, rocket motors, petroleum products (including crude oil drilling or production, natural gas, etc.). 
         [0208]    Typically, these facilities  253  may include towers, elevated structures  252 , or platforms  252  containing buildings, operation rooms, control rooms, and the like. Accordingly, the structure  252  of a particular facility  253  will support operational equipment and employees or workers who are potential users  45  (riders  45 ) of a system  10  in accordance with the invention. Typically, the structure  252  is an inherent structure  252  required by the central function of a facility  253  that has a potential for danger. 
         [0209]    For example, a fire on a remote drilling or petroleum production platform  252  may be devastating, with no ready means of escape. Moreover, when the structure  252  is part of or is associated with a facility  253  having a tower or elevated surfaces, egress in an emergency situation, where time is of the essence, may be difficult to impossible. Thus, connecting beams  254  may be attached to the structure  252 . 
         [0210]    Connecting beams  254  may be secured by various fastening mechanisms to support beams  256  constituting a portion of the structure  252  of a facility  253 . To the connecting beams  254  may be secured rails  260 . Typically, a single rail  260  may be adequate. In some embodiments, multiple rails  260  may be scattered about various beams  256  of a structure  252  in order to provide timely and close access to workers in an emergency egress situation. 
         [0211]    Meanwhile, a fin  263  may be specially constructed, or may simply be adapted by providing apertures  262  in a flange  263  of a pillar  258  supporting the structure  252  or as another part of the structure  252 . In other embodiments, a distinct fin  263  may be secured to the structure  252  at an appropriate place and with the appropriate engineering and construction procedures. 
         [0212]    In the illustrated embodiment, a termination  266  of the cable  20  or track line  20  may be constituted as a clevis  266  secured to the fin  263  by a fastener  268 , such as a pin  268 . 
         [0213]    In the illustrated embodiment, a turnbuckle  272  and a retrieval spring  274  or another type of resilient member  274  (e.g., leaf spring, compression spring, elastic band, or the like) may secure in any appropriate geometry between an eye  270  at the lower end of the turnbuckle  272 , and a bracket  278  secured to the rail  260 . The bottom ends of the turnbuckle  272  and an extension coil spring  274  may typically connect directly together. However, how connection is done represents an optional construction configuration. 
         [0214]    The guard  276  about a turnbuckle  272  permits pivoting of a turnbuckle  272  about a pin  269 . For example, a bracket  278  securing each pivot  279  or pin  279  supports the pivoting of springs  274  and turnbuckles  272 . The bracket  276  may limit the amount of pivot of a turnbuckle  272 . Meanwhile, the brackets  278  support in a vertical direction, and secure to pivot thereabout, each of the turnbuckles  272  and springs  274  pivotably secured by the pins  279  or to the pins  279 . 
         [0215]    In some embodiments, a hook or loop at the lower end of the spring  274  may secure to the eye  272  at the lower end of the turnbuckle  272 . In other embodiments, the spring  274  may secure at a different location to the turnbuckle  272 . In operation, the rail  260 , a spring  274 , and a turnbuckle  272  may be configured to define an approximately triangulated shape. Typically, in geometry, a triangle has three fixed sides, which together establish angles at the vertices (connections between sides) of a triangle. 
         [0216]    In the illustrated embodiment, the springs  274  represent a side of each triangle, which side is extensible. Accordingly, the springs  274  may be extended in order to swing the turnbuckles  272  each around their respective pins  279  or pivots  279  in the brackets  278 . Accordingly, the weight of a trolley  50  may be supported by the rail  260  through the triangulated turnbuckle  272  and spring  274  associated therewith. 
         [0217]    For example, multiple turnbuckles  272   a ,  272   b  secure to corresponding springs  274   a ,  274   b . The springs  274  may support part of the load. However, the bulk of the load represented by the weight of a rider  45  in a seat  46  or harness system  46  suspended from a trolley  50  may eventually be supported entirely by a turnbuckle  272 . The turnbuckle  272  may orient fully vertically by virtue of the overwhelming weight supported thereby causing enough extension of the corresponding spring  274  to create that geometry. 
         [0218]    In operation, the turnbuckle  272  is secured, typically through an eye  270  to a brake system  58  (the caboose portion  58 ) of a trolley  50 . In the illustrated embodiment, a release link  108  may be configured to have the components  69  such as a snap shackle loop  69   a , catch  69   b , pin  69   c , and some actuator  69   d . However, other types of release links  108  may be used to answer the need. An individual user may trigger a release link  108  to free the connection  108  between the eye  270  of a turnbuckle  272  and a particular trolley  50 . Every rider  45  of a trolley  50  may have complete control of that trolley  50 . 
         [0219]    The operation of the trolley  50  may be constrained by the presence of another trolley  50  nearby. However, a front bumper  104  and a rear bumper  105  make possible the operation of multiple trolleys  50  in tandem. In fact, the rear bumper  105  may include an impact surface  106  with a pilot  107  or a side wings  107  to guide the front bumper  104  of a trailing trolley  50  into the rear bumper  105  of a forward trolley  50 . 
         [0220]    As a practical matter, once in operation, an individual rider  45  has access to a handle  57  drawing on a tether  56  to control the position of the slide  54  or hanger  54  traveling back and forth along the arm  52  or lever  52  that actuates the brake assembly  58 . As described hereinabove, drawing the slide  54  backward along the arm  52  by the force applied on the tether  56  through the handle  57 , reduces a distance and therefor leverage of the weight of a rider  45 . This action relieves the brake pad  59  force from contact with the track line  20 . Accordingly, a trolley  50  begins moving downhill once a rider  45  has released the braking effect. 
         [0221]    Referring to  FIG. 18 , while continuing to refer generally to  FIGS. 1 through 18 , the structure  252  supporting a carrier system  250  may rely on triggering by a rider  45  seated in a seat  46  or harness  46  suspended under a trolley  50 . A rider  45  will necessarily need access to the release link  108  securing a trolley  50  to the eye  270  of a turnbuckle  272 . In order to do this, some mechanism of control is necessary. 
         [0222]    A rider  45  in a seat  46 , may be supported principally by the actual seat panel  64  under a rider  45 . Meanwhile, a yoke  282  may operate much as the handle  57  described hereinabove. In fact, one may think of the yoke  282  as the handle  57 . The yoke  282  may be wider, and may be shaped to provide more clearance above a user, while placing the handles  280  or grips  280  comparatively lower than the point of suspension by the yoke  282  secured to the tether  56  thereabove. 
         [0223]    As described hereinabove, the tether  56  extends from the yoke  282  up into the trolley  50 , ultimately drawing the slide  54  or hanger  54  rearward or backward along the arm  52 . Accordingly, the effective length of the lever arm  52  by which the trolley  50  pivots about the axle  72  is reduced. This reduces the effective force applied by the brake pad  59  against the track line  20 . 
         [0224]    In the illustrated embodiment, additional connections may be made between the harness  46  or seat  46  and the trolley  50 . For example, a belay sling  55  or safety sling  55  may connect from the trolley  50  to the harness  46 . However, operationally, the principal weighting of the harness  46  and its contained rider  45  is directed to the spreader  65  suspended from the slide  54  on the arm  52 . 
         [0225]    In the illustrated embodiment, the grips  280  on the yoke  282  may be provided with additional triggers  284 . The triggers  284  will typically connect to cables  286 . The cables  286  are best and easiest to install as sheathed cables  286 . Sheathed cables are used in a control of bicycle brakes, motorcycle controls, and the like near handle grips. Here, the grips  280  are configured to allow a rider  45  to hang on to the tether  56  in order to release the trolley brake  58  and move forward. 
         [0226]    Upon releasing or reducing force on the yoke  282 , a user permits the tether  56  to release the force applied to the slide  54 , thus permitting the slide  54  to move forward on the arm  52 . The resultant increasing leverage against the brake  58  applies more force between the brake pad  59  and the track line  20 . 
         [0227]    An important function of the triggers  284  is to provide a trigger  284  actuating a mechanism (such as a pin  69   c ) releasing the snap shackle loop  69   a  or other securement element  69 . Importantly, release must occur while supporting the binding force from the weight of a trolley  50  and rider  45  suspended from the eye  270  of a turnbuckle  272 . In the illustrated embodiment, the triggers  284  or handles  284  are doubled to be redundant. Either one operates the sheathed cable  286  to release the link  108  by opening the snap shackle loop  69   a.    
         [0228]    The significance of suspending each trolley  50  from a turnbuckle  272  is that it reduces the loading on the track line  20 . Operating as a catenary  20 , the track line  20  is suspended between an upper station  12  and a lower station  22 . Its shape changes by adding “point loads” (an engineering term) at an upper station  12 . The turnbuckles  272  take the rider weight and thus maintain the stability of the catenary  26  shape. Track lines  20  may typically be one quarter, one half, or even a full inch in diameter. Part of that sizing depends on the length of the suspended track line  20  supported. A one mile distance covered by a track line  20  represents substantial weight. A track line  20  extending 500 to 1000 feet need not be as large, because it does not have nearly so much of its own weight to support. 
         [0229]    However, adding multiple riders at a single point (effectively) on a catenary  26  as a track line  20  has consequences that can interfere with proper loading and launch. For example, five large men could easily weigh over 1000 pounds total. That much weight applied to a comparatively smaller track line  20  extending a comparatively short distance (for example, a half inch line extending 700 feet) would be dramatically affected by the weight of the riders  45 . In fact, the harnesses  46  might all hit the launch deck  14 , thus making difficult or impossible the launching of trolleys  50 . However, by the turnbuckle  272  above each trolley  50  supporting the weight of the trolley, the track line  20  becomes free to suspend in its normal shape. Once launched, the spring  274  pulls its corresponding turnbuckle  272  up and out of the way. The line  20  immediately responds to the weight of the rider  45  as a point load moving downward along its length. Each rider  45  launched increases tension in the line  20 , reducing the influence of the next launch on the shape of the line  20  and its distance from the launch dock  14 . 
         [0230]    Upon launch, each individual rider  45  has control of the corresponding trolley  50  by operating the yoke  282  through the grips  280 , and operating the trigger  284  to activate the release link  108 . The natural delay between individual people will provide a time of from about one to about five seconds difference between adjacent riders  45 . Accordingly, each rider  45  will load into a seat  46 , then pull down on the grips  280  and activate the trigger  284  to release the release link  108 . 
         [0231]    Whether the trigger  284  is pulled first, or the handles  280  are pulled first is not critical. However, multiple riders  45  all pulling at triggers  284  first, without drawing on the grips  280  could create a problem. Accordingly, a best practice is for a rider to sit in the seat  46 , placing the arms through the webbing supporting the seat panel  64 . Drawing down on the grips  280  of the handle  57  (yoke of  282 ) before pulling on the trigger  284 . The first rider  45  immediately launches, and the subsequent riders  45  may then, in turn, pull on the triggers  284  of their corresponding yokes  282  in order to launch each of them. 
         [0232]    As a practical matter, once a rider  45  has launched down the track line  20 , the weight of that rider  45  begins immediately to increase the total weight on the catenary  20  at a distance away from the upper station  12 . The rider  45  becomes a point load moving away from the upper station  12 . This further improves the stability of the position of the track line  20  above the upper deck  14 . Once multiple riders  45  are under way along the track line  20 , subsequent riders  45  will have much less effect on the height of the track line  20  above the deck  14 . 
         [0233]    Thus, the carrier system  250  made up of the turnbuckles  272  and springs  274  suspended from the brackets  278  by pins  279  provides support for all riders  45  being loaded into harnesses  46  simultaneously, especially with their weight applied simultaneously to the carrier system  250 . In an alternative embodiment, the turnbuckles  272  may be replaced by another type of link  272 , such as a length of chain  272  terminating with a carabiner or other link easily connected to snap shackle on a trolley  50 . 
         [0234]    Since chain can be cut to any length, the beams  254 ,  256  need not conform to the angle of the catenary  20  with respect to the main structure  252 . Each chain  272  may be cut to length to end just above the track line  20 . It may be terminated with a loop shaped to present a sufficiently large opening in the direction of the track line  20  for receiving a snap shackle  69   a  or other release mechanism  68 . The spring  274  may be in any suitable shape and orientation, including a bungee (elastic) cord running parallel to a chain  272  and captured therewith inside a protective, flexible sheath or tube. 
         [0235]    Release of a trolley  50 , also releases the portion of the track line  20  on which that trolley  50  engages (rollably secures). This results in unloading, and therefore lifting, such a chain  272  away from the track line  20  and the next trolley  50  in line to release. However, each trolley  50  should naturally clear the link  272  left by a previously departing trolley  50 , since the track line  20  will typically drop slightly with each launch as the suspension point of the track line changes. 
         [0236]    The supporting carrier system  250  maintains the track line  20  above the loading deck, on the wheels of the trolleys it suspends. Each trolley launched weights the track line, acting as a point load (in engineering parlance) moving therealong. By not releasing the triggers  284  simultaneously, but individually, in sequence, as each rider  45  readies and launches, the riders  45  naturally create a separation distance between them, along the track line  20 . Individual braking provides each rider  45  complete control against collision with a previously launched trolley. 
         [0237]    A system  10  in accordance with the invention may also be used for mass transit across geographic barriers, such as highways, trains, gorges, rivers, or other obstructions. Trolleys  50  may each suspend a simple harness, comfortable seat, individual gondola, or group cabin therebelow. Riders may load and launch individually or in small groups to cross in one direction early in a day, then mount a tower at the end of the day to return on a track line  20  and trolley  50  traveling in the opposite direction. The elements providing for individual control of launch and travel provide a throughput of several trolleys per minute, even mere seconds (single digits) apart in actual practice 
         [0238]    The present invention may be embodied in other specific forms without departing from its purposes, functions, structures, or operational characteristics. The described embodiments are to be considered in all respects only as illustrative, and not restrictive. The scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.