§ 238.5 Definitions. As used in this part— *AAR* means the Association of American Railroads.
*APTA* means the American Public Transportation Association.
*Actuator* means a self-contained brake system component that generates the force to apply the brake shoe or brake pad to the wheel or disc. An actuator typically consists of a cylinder, piston, and piston rod.
*Administrator* means the Administrator of the Federal Railroad Administration or the Administrator's delegate.
*Alerter* means a device or system installed in the locomotive cab to promote continuous, active locomotive engineer attentiveness by monitoring select locomotive engineer-induced control activities. If fluctuation of a monitored locomotive engineer-induced control activity is not detected within a predetermined time, a sequence of audible and visual alarms is activated so as to progressively prompt a response by the locomotive engineer. Failure by the locomotive engineer to institute a change of state in a monitored control, or acknowledge the alerter alarm activity through a manual reset provision, results in a penalty brake application that brings the locomotive or train to a stop.
*Anti-climbing mechanism* means the parts at the ends of adjoining vehicles in a train that are designed to engage when subjected to large buff loads to prevent the override of one vehicle by another.
*Associate Administrator* means Associate Administrator for Railroad Safety and Chief Safety Officer, Associate Administrator for Railroad Safety, Associate Administrator for Safety.
*Bind* means restrict the intended movement of one or more brake system components by obstruction, increased friction, or reduced clearance.
*Block of cars* means one car or multiple cars in a solid unit coupled together for the purpose of being added to, or removed from, a train as a solid unit.
Brake, air or power brake means a combination of devices operated by compressed air, arranged in a system, and controlled manually, electrically, or pneumatically, by means of which the motion of a rail car or locomotive is retarded or arrested.
*Brake, disc* means a retardation system used on some rail vehicles, primarily passenger equipment, that utilizes flat metal discs as the braking surface instead of the wheel tread.
*Brake, dynamic* means a train braking system whereby the kinetic energy of a moving train is used to generate electric current at the locomotive traction motors, which is then dissipated through banks of resistor grids or back into the catenary or third rail system.
*Brake, effective* means a brake that is capable of producing its required designed retarding force on the train. A brake is not effective if its piston travel is in excess of the maximum prescribed limits. On vehicles equipped with nominal 12-inch stroke brake cylinders, the brake is not effective if its piston travel exceeds 101 ⁄ 2 inches.
*Brake indicator* means a device, actuated by brake cylinder pressure, which indicates whether brakes are applied or released.
*Brake, inoperative* means a primary brake that, for any reason, no longer applies or releases as intended or is otherwise ineffective.
*Brake, on-tread friction* means a braking system that uses a brake shoe that acts on the tread of the wheel to retard the vehicle.
Brake, parking or hand brake means a brake that can be applied and released by hand to prevent movement of a stationary rail car or locomotive.
*Brake pipe* means the system of piping (including branch pipes, angle cocks, cutout cocks, dirt collectors, hoses, and hose couplings) used for connecting locomotives and all rail cars for the passage of air to control the locomotive and car brakes.
*Brake, power* means “air brake” as that term is defined in this section.
*Brake, primary* means those components of the train brake system necessary to stop the train within the signal spacing distance without thermal damage to friction braking surfaces.
*Brake, secondary* means those components of the train brake system which develop supplemental brake retarding force that is not needed to stop the train within signal spacing distances or to prevent thermal damage to friction braking surfaces.
*Brake shoes or pads aligned with tread or disc* means that the surface of the brake shoe or pad, respectively, engages the surface of the wheel tread or disc, respectively, to prevent localized thermal stress.
*Braking system, blended* means a braking system where the primary brake and one or more secondary brakes are automatically combined to stop the train. If the secondary brakes are unavailable, the blended brake uses the primary brake alone to stop the train.
*By-pass* means a device designed to override a function.
*Calendar day* means a time period running from one midnight to the next midnight on a given date.
*Class I brake test* means a complete passenger train brake system test and inspection (as further specified in § 238.313) performed by a qualified maintenance person to ensure that the air brake system is 100 percent effective.
*Class IA brake test* means a test and inspection (as further specified in § 238.315) performed by a qualified person of the air brake system on each car in a passenger train to ensure that the brakes apply and release on each car in the train in response to train line commands.
*Class II brake test* means a test and inspection (as further specified in § 238.317) performed by a qualified person of brake pipe integrity and continuity from the controlling locomotive to the rear unit of a passenger train.
*Collision posts* means structural members of the end structures of a vehicle that extend vertically from the underframe to which they are securely attached and that provide protection to occupied compartments from an object penetrating the vehicle during a collision.
*Control valves* means that part of the air brake equipment on each rail car or locomotive that controls the charging, application, and release of the air brakes, in response to train line commands.
*Corner posts* means structural members located at the intersection of the front or rear surface with the side surface of a rail vehicle and which extend vertically from the underframe to the roof. Corner posts may be combined with collision posts to become part of the end structure.
*Crack* means a fracture without complete separation into parts, except that, in a casting, a shrinkage crack or hot tear that does not significantly diminish the strength of the member is not a crack.
*Crash energy management* means an approach to the design of rail passenger equipment which controls the dissipation of energy during a collision to protect the occupied volumes from crushing and to limit the decelerations on passengers and crewmembers in those volumes. This may be accomplished by designing energy-absorbing structures of low strength in the unoccupied volumes of a rail vehicle or passenger train to collapse in a controlled manner, while providing higher structural strength in the occupied volumes. Energy deflection can also be part of a crash energy management approach. Crash energy management can be used to help provide anti-climbing resistance and to reduce the risk of train buckling during a collision.
*Crash refuge* means a volume with structural strength designed to maximize the survivability of crewmembers stationed in the locomotive cab during a collision.
*Crewmember* means a railroad employee called to perform service covered by the Federal hours of service laws at 49 U.S.C. 21103 and subject to the railroad's operating rules and program of operational tests and inspections required in § 217.9 and § 217.11 of this chapter.
*Critical buckling* stress means the minimum stress necessary to initiate buckling of a structural member.
*Door isolation lock* means a cutout/lockout mechanism installed at each exterior side door panel to secure a door in the closed and latched position, provide a door-closed indication to the summary circuit, and remove power from the door motor or door motor controls.
*Door summary circuit* means a trainline door circuit that provides an indication to the controlling cab of the train that all exterior side doors are closed as intended, or locked out with a door isolation lock, or both.
*Dual-function window* means a window that is intended to serve as both an emergency window exit and a rescue access window and that meets the applicable requirements set forth in both §§ 238.113 and 238.114.
*Emergency brake application* means an irretrievable brake application resulting in the maximum retarding force available from the train brake system.
*Emergency responder* means a member of a police or fire department, or other organization involved with public safety charged with providing or coordinating emergency services, who responds to a passenger train emergency.
*Emergency window* means the segment of a side-facing glazing panel that has been designed to permit rapid and easy removal from inside a passenger car in an emergency situation.
End- frame door means an end-facing door normally located between, or adjacent to, the collision posts or similar end-frame structural elements.
*End-of-train circuit* means a feature typically used to determine the physical end of the train, or the last passenger car in the train, or both, for the door summary circuit.
*End structure* means the main support structure projecting upward from the underframe of a locomotive, passenger car, or other rail vehicle. The end structure is securely attached to the underframe at each end of a rail vehicle.
*Exterior side door safety system* means a system of safety features that enable the safe operation of the exterior side doors of a passenger car or train. The exterior side door safety system includes appurtenances and components that control, operate, and display the status of the exterior side doors, and is interlocked with the train's traction power control.
*50th-percentile adult male* means a person weighing 164 pounds (plus or minus 3 pounds) and possessing the following dimensions: erect sitting height: 35.7 inches (plus or minus 0.1 inch); hip breadth (sitting): 14.7 inches (plus or minus 0.7 inch); hip circumference (sitting): 42 inches; waist circumference (sitting): 32 inches (plus or minus 0.6 inch); chest depth: 9.3 inches (plus or minus 0.2 inch); and chest circumference: 37.4 inches (plus or minus 0.6 inch).
*Foul* means restrict the intended movement of one or more brake system components because the component is snagged, entangled, or twisted.
*FRA* means the Federal Railroad Administration.
*Fuel tank, external* means a fuel containment vessel that extends outside the car body structure of a locomotive.
*Fuel tank, internal* means a fuel containment vessel that does not extend outside the car body structure of a locomotive.
*Full-height collision post, corner post,* or side frame post means any vertical framing member in the rail car body structure that spans the distance between the underframe and the roof at the car body section where the post is located. For collision posts located at the approximate third points laterally of an end frame, the term “full-height” applies to posts that extend and connect to supporting structural members in the roof at the location of the posts, or to a beam connected to the top of the end-frame and supported by the roof rails (or anti-telescoping plate), or to both.
*Full service application* means a brake application which results in a brake cylinder pressure at the service limiting valve setting or equivalent.
*Glazing, end-facing* means any exterior glazing located where a line perpendicular to the plane of the glazing material makes a horizontal angle of 50 degrees or less with the centerline of the vehicle in which the glazing material is installed, except for: The coupled ends of multiple-unit (MU) locomotives or other equipment semi-permanently connected to each other in a train consist; and end doors of passenger cars at locations other than the cab end of a cab car or MU locomotive. Any location which, due to curvature of the glazing material, can meet the criteria for either an end-facing glazing location or a side-facing glazing location shall be considered an end-facing glazing location.
*Glazing, exterior* means a glazing panel that is an integral part of the exterior skin of a rail vehicle and has a surface exposed to the outside environment.
*Glazing, side-facing* means any glazing located where a line perpendicular to the plane of the glazing material makes a horizontal angle of more than 50 degrees with the centerline of the vehicle in which the glazing material is installed. Side-facing glazing also means glazing located at the coupled ends of MU locomotives or other equipment semi-permanently connected to each other in a train consist and glazing located at end doors other than at the cab end of a cab car or MU locomotive.
*Handrails* means safety appliances installed on either side of a rail vehicle's exterior doors to assist passengers and crewmembers to safely board and depart the vehicle.
*Head end power* means power generated on board the locomotive of a passenger train used for purposes other than propelling the train, such as cooking, heating, illumination, ventilation and air conditioning.
*In passenger service/in revenue service* means a train or passenger equipment that is carrying, or available to carry, passengers. Passengers need not have paid a fare in order for the equipment to be considered in passenger or in revenue service.
*In service,* when used in connection with passenger equipment, means: ( 1 ) Passenger equipment subject to this part that is in passenger or revenue service in the United States; and
( 2 ) All other passenger equipment subject to this part in the United States, unless the passenger equipment: ( i ) Is being handled in accordance with §§ 238.15, 238.17, 238.305(d), or 238.503(f), as applicable;
( ii ) Is in a repair shop or on a repair track;
( iii ) Is on a storage track and is not carrying passengers; or
( iv ) Has been delivered in interchange but has not been accepted by the receiving railroad.
*Intercom* means a device through which voice communication is transmitted and received.
*Intercom system* means a two-way, voice communication system.
*Interior fitting* means any component in the passenger compartment which is mounted to the floor, ceiling, sidewalls, or end walls and projects into the passenger compartment more than 25 mm (1 in.) from the surface or surfaces to which it is mounted. Interior fittings do not include side and end walls, floors, door pockets, or ceiling lining materials, for example.
*Intermediate level* means a level of a multi-level passenger car that is used for passenger seating and is normally located between two main levels. An intermediate level normally contains two, separate seating areas, one at each end of the car, and is normally connected to each main level by stairs.
*Lateral* means the horizontal direction perpendicular to the direction of travel.
*Locomotive* means a piece of on-track rail equipment, other than hi-rail, specialized maintenance, or other similar equipment, which may consist of one or more units operated from a single control stand with one or more propelling motors designed for moving other passenger equipment; with one or more propelling motors designed to transport freight or passenger traffic, or both; or without propelling motors but with one or more control stands. This term does not include a locomotive propelled by steam power unless it is used to haul an intercity or commuter passenger train. Nor does this term include a freight locomotive when used to haul a passenger train due to failure of a passenger locomotive.
*Locomotive cab* means the compartment or space on board a locomotive where the control stand is located and which is normally occupied by the engineer when the locomotive is operated.
*Locomotive, cab car* means rail rolling equipment intended to provide transportation for members of the general public that is without propelling motors but equipped with one or more control stands.
*Locomotive, controlling* means the locomotive from which the locomotive engineer exercises control over the train.
*Locomotive, MU* means rail rolling equipment self-propelled by any power source and intended to provide transportation for members of the general public; however, this term does not include an MU locomotive propelled by steam power unless it is used to haul an intercity or commuter passenger train.
*Longitudinal* means in a direction parallel to the normal direction of travel.
*Luminescent material* means material that absorbs light energy when ambient levels of light are high and emits this stored energy when ambient levels of light are low, making the material appear to glow in the dark.
*L/V ratio* means the ratio of the lateral force that any wheel exerts on an individual rail to the vertical force exerted by the same wheel on the rail.
*Main level* means a level of a passenger car that contains a passenger compartment whose length is equal to or greater than half the length of the car.
*MIL-STD-882* means a military standard issued by the United States Department of Defense to provide uniform requirements for developing and implementing a system safety plan and program to identify and then eliminate the hazards of a system or reduce the associated risk to an acceptable level.
*Mph* means miles per hour.
*95th-percentile adult male* means, except as used in § 238.447(f)(2), a person weighing 215 pounds and possessing the following dimensions: erect sitting height: 38 inches; hip breadth (sitting): 16.5 inches; hip circumference (sitting): 47.2 inches; waist circumference (sitting): 42.5 inches; chest depth: 10.5 inches; and chest circumference 44.5 inches.
*No-motion system* means a system on a train that detects the motion of the train.
*Occupied volume* means the volume of a rail vehicle or passenger train where passengers or crewmembers are normally located during service operation, such as the operating cab and passenger seating and sleeping areas. The entire width of a vehicle's end compartment that contains a control stand is an occupied volume. A vestibule is typically not considered occupied, except when it contains a control stand for use as a control cab.
*Ordered,* as applied to acquisition of equipment, means that the acquiring entity has given a notice to proceed to manufacture the equipment that represents a firm financial commitment to compensate the manufacturer for the contract price of the equipment or for damages if the order is nullified. Equipment is not ordered if future exercise of a contract option is required to place the remanufacturing process in motion.
*Override* means to climb over the normal coupling or side buffers and linking mechanism and impact the end of the adjoining rail vehicle or unit above the underframe.
*PA system* (or *public address system*) means a one-way, voice communication system.
*Passenger car* means rail rolling equipment intended to provide transportation for members of the general public and includes a self-propelled car designed to carry passengers, baggage, mail, or express. This term includes a passenger coach, cab car, and an MU locomotive. In the context of articulated equipment, “passenger car” means that segment of the rail rolling equipment located between two trucks. This term does not include a private car.
*Passenger coach* means rail rolling equipment intended to provide transportation for members of the general public that is without propelling motors and without a control stand.
*Passenger compartment* means an area of a passenger car that consists of a seating area and any vestibule that is connected to the seating area by an open passageway.
*Passenger equipment* —means ( 1 ) All powered and unpowered passenger cars, locomotives used to haul a passenger car, and any other rail rolling equipment used in a train with one or more passenger cars. Passenger equipment includes— ( i ) A passenger coach,
( ii ) A cab car,
( iii ) A MU locomotive,
( iv ) A locomotive not intended to provide transportation for a member of the general public that is used to power a passenger train, and
( v ) Any non-self-propelled vehicle used in a passenger train, including an express car, baggage car, mail car, freight car, or a private car.
( 2 ) In the context of articulated equipment, “passenger equipment” means a segment of rail rolling equipment located between two trucks that is used in a train with one or more passenger cars. This term does not include a freight locomotive when used to haul a passenger train due to failure of a passenger locomotive.
*Passenger station* means a location designated in a railroad's timetable where passengers are regularly scheduled to get on or off any train.
*Permanent deformation* means the undergoing of a permanent change in shape of a structural member of a rail vehicle.
*Person* means an entity of any type covered under 1 U.S.C. 1, including but not limited to the following: a railroad; a manager, supervisor, official, or other employee or agent of a railroad; any owner, manufacturer, lessor, or lessee of railroad equipment, track, or facilities; any independent contractor providing goods or services to a railroad; and any employee of such owner, manufacturer, lessor, lessee, or independent contractor.
*Piston travel* means the amount of linear movement of the air brake hollow rod (or equivalent) or piston rod when forced outward by movement of the piston in the brake cylinder or actuator and limited by the brake shoes being forced against the wheel or disc.
*Piston travel indicator* means a device directly activated by the movement of the brake cylinder piston, the disc brake actuator, or the tread brake unit cylinder piston that provides an indication of the piston travel.
*Power car* means a rail vehicle that propels a Tier II passenger train or is the lead vehicle in a Tier II passenger train, or both.
*Pre-revenue service acceptance testing plan* means a document, as further specified in § 238.111, prepared by a railroad that explains in detail how pre-revenue service tests of passenger equipment demonstrate that the equipment meets Federal safety standards and the railroad's own safety requirements.
*Primary responsibility* means the task that a person performs during at least 50 percent of the time that the person is working. The totality of the circumstances will be considered on a case-by-case basis in circumstances where an individual does not spend 50 percent of his or her workday engaged in any one readily identifiable type of activity. Time spent supervising employees engaged in the functions of troubleshooting, inspection, testing, maintenance, or repair of train brake and mechanical components and systems covered by this part shall be considered work which is generally consistent with the function of troubleshooting of such systems and components for the purpose of the definition of this term and the definition of “Qualified Maintenance Person.”
*Private car* means rail rolling equipment that is used only for excursion, recreational, or private transportation purposes. A private car is not a passenger car.
*Public highway-rail grade crossing* means a location where a public highway, road or street, including associated sidewalks or pathways, crosses one or more active railroad tracks at grade.
*Qualified maintenance person* means a qualified person who has received, as a part of the training, qualification, and designation program required under § 238.109, instruction and training that includes “hands-on” experience (under appropriate supervision or apprenticeship) in one or more of the following functions: troubleshooting, inspection, testing, maintenance, or repair of the specific train brake and other components and systems for which the person is assigned responsibility. This person shall also possess a current understanding of what is required to properly repair and maintain the safety-critical brake or mechanical components for which the person is assigned responsibility. Further, the qualified maintenance person shall be a person whose primary responsibility includes work generally consistent with the above-referenced functions and is designated to: ( 1 ) Conduct Class I brake tests under this part;
( 2 ) Conduct exterior calendar day mechanical inspections on MU locomotives or other passenger cars and unpowered vehicles under this part; or
( 3 ) Determine whether equipment not in compliance with this part may be moved as required by § 238.17.
*Qualified person* means a person who has received, as a part of the training, qualification, and designation program required under § 238.109, instruction and training necessary to perform one or more functions required under this part. The railroad is responsible for determining that the person has the knowledge and skills necessary to perform the required function for which the person is assigned responsibility. The railroad determines the qualifications and competencies for employees designated to perform various functions in the manner set forth in this part. Although the rule uses the term “qualified person” to describe a person responsible for performing various functions required under this part, a person may be deemed qualified to perform some functions but not qualified to perform other functions. For example, although a person may be deemed qualified to perform the Class II brake test required by this part, that same person may or may not be qualified to perform the Class IA brake test or authorize the movement of defective equipment under this part. The railroad will determine the required functions for which an individual will be deemed a “qualified person” based upon the instruction and training the individual has received pursuant to § 238.109 on a particular function.
*Railroad* means any form of nonhighway ground transportation that runs on rails or electromagnetic guideways and any entity providing such transportation, including— ( i ) Commuter or other short-haul railroad passenger service in a metropolitan or suburban area and commuter railroad service that was operated by the Consolidated Rail Corporation on January 1, 1979; and
( ii ) High speed ground transportation systems that connect metropolitan areas, without regard to whether those systems use new technologies not associated with traditional railroads; but does not include rapid transit operations in an urban area that are not connected to the general railroad system of transportation.
*Refresher training* means periodic retraining required by a railroad for employees or contractors to remain qualified to perform specific equipment inspection, testing, or maintenance functions.
*Repair point* means a location designated by a railroad where repairs of the type necessary occur on a regular basis. A repair point has, or should have, the facilities, tools, and personnel qualified to make the necessary repairs. A repair point need not be staffed continuously.
*Rescue access window* means a side-facing exterior window intended for use by emergency responders to gain access to passengers in an emergency situation.
*Respond as intended* means to produce the result that a device or system is designed to produce.
*Retroreflective material* means a material that is capable of reflecting light rays back to the light source and that conforms to the specifications for Type I Sheeting as specified in ASTM International Standard D 4956-07, “Standard Specification for Retroreflective Sheeting for Traffic Control.” The Director of the Federal Register approves the incorporation by reference of this standard in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. You may obtain a copy of the incorporated standard from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959. You may inspect a copy of the incorporated standard at the Federal Railroad Administration, Docket Clerk, 1200 New Jersey Avenue, SE., Washington, DC, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to *http://www.archives.gov/federal-register/cfr/ibr-locations.html .*
*Rollover strength* means the strength provided to protect the structural integrity of a rail vehicle in the event the vehicle leaves the track and impacts the ground on its side or roof.
*Roof rail* means the longitudinal structural member at the intersection of the side wall and the roof sheathing.
*Running brake test* means a test (as further specified in § 238.319) performed by a qualified person of a train system or component while the train is in motion to verify that the system or component functions as intended.
*Running gear defect* means any condition not in compliance with this part which involves a truck component, a draft system component, a wheel, or a wheel component.
*Safety appliance* means an appliance required under 49 U.S.C. chapter 203, excluding power brakes. The term includes automatic couplers, hand brakes, sill steps, handholds, handrails, or ladder treads made of steel or a material of equal or greater mechanical strength used by the traveling public or railroad employees that provide a means for safely coupling, uncoupling, or ascending or descending passenger equipment.
*Safety-critical* means a component, system, or task that, if not available, defective, not functioning, not functioning correctly, not performed, or not performed correctly, increases the risk of damage to passenger equipment or injury to a passenger, crewmember, or other person.
*Seating area* means an area of a passenger car that normally contains passenger seating.
*Semi-permanently coupled* means coupled by means of a drawbar or other coupling mechanism that requires tools to perform the uncoupling operation. Coupling and uncoupling of each semi-permanently coupled unit in a train can be performed safely only while at a maintenance or shop location where personnel can safely get under a unit or between units.
*Semi-monocoque* means a type of rail vehicle construction where the shell or skin acts as a single unit with the supporting frame to resist and transmit the loads acting on the rail vehicle.
*Shear strength* means the ability of a structural member to resist forces or components of forces acting perpendicular to compression or tension forces, or both, in the member.
*Shock absorbent material* means material designed to prevent or mitigate injuries due to impact by yielding and absorbing much of the energy of impact.
*Side posts* means main vertical structural elements in the sides of a rail vehicle.
*Side sill* means that portion of the underframe or side at the bottom of the rail vehicle side wall.
*Single car test* means a comprehensive test (as further specified in § 238.311) of the functioning of all critical brake system components installed on an individual passenger car or unpowered vehicle, other than a self-propelled passenger car, used or allowed to be used in a passenger train.
*Single car test* device means a device capable of controlling the application and release of the brakes on an individual passenger car or an unpowered vehicle, other than a self-propelled passenger car, through pneumatic or electrical means.
*Skin* means the outer covering of a fuel tank and a rail vehicle. The skin may be covered with another coating of material such as fiberglass.
*Spall, glazing* means small pieces of glazing that fly off the back surface of the glazing when an object strikes the front surface.
*Switching service* means the classification of freight cars according to commodity or destination; assembling of cars for train movements; changing the position of cars for purposes of loading, unloading, or weighing; placing of locomotives and cars for repair or storage; or moving of rail equipment in connection with work service that does not constitute a train movement.
*Telescope* means override an adjoining rail vehicle or unit and penetrate into the interior of that adjoining vehicle or unit because of compressive forces.
*Terminal* means a starting point or ending point of a single scheduled trip for a train, where passengers may get on or off a train. Normally, this location is a point where the train would reverse direction or change destinations.
*Tier I* means operating at speeds not exceeding 125 mph.
*Tier II* means operating at speeds exceeding 125 mph but not exceeding 160 mph.
*Tier III* means operating in a shared right-of-way at speeds not exceeding 125 mph and in an exclusive right-of-way without grade crossings at speeds exceeding 125 mph but not exceeding 220 mph.
*Tourist, scenic, historic, or excursion operations* means railroad operations that carry passengers, often using antiquated equipment, with the conveyance of the passengers to a particular destination not being the principal purpose. Train movements of new passenger equipment for demonstration purposes are not tourist, scenic, historic, or excursion operations.
*Trailer car* means a rail vehicle that neither propels a Tier II passenger train nor is the leading unit in a Tier II passenger train. A trailer car is normally without a control stand and is normally occupied by passengers.
*Train* means a locomotive unit or locomotive units coupled, with or without cars. For the purposes of the provisions of this part related to power brakes, the term “train” does not include such equipment when being used in switching service.
*Train brake communication line* means the communication link between the locomotive and passenger equipment in a train by which the brake commands are transmitted. This may be a pneumatic pipe, electrical line, or radio signal.
*Train, commuter* means a passenger train providing commuter service within an urban, suburban, or metropolitan area. The term includes a passenger train provided by an instrumentality of a State or a political subdivision of a State.
*Trainline door circuit* means a circuit used to convey door signals over the length of a train.
*Train, long-distance intercity passenger* means a passenger train that provides service between large cities more than 125 miles apart and is not operated exclusively in the National Railroad Passenger Corporation's Northeast Corridor.
*Train, passenger* means a train that transports or is available to transport members of the general public. If a train is composed of a mixture of passenger and freight equipment, that train is a passenger train for purposes of this part.
*Train, short-distance intercity passenger* means a passenger train that provides service exclusively on the National Railroad Passenger Corporation's Northeast Corridor or between cities that are not more than 125 miles apart.
*Train, Tier II passenger* means a short-distance or long-distance intercity passenger train providing service at speeds exceeding 125 mph but not exceeding 160 mph.
*Trainset, passenger* means a passenger train.
*Trainset, Tier I alternative passenger* means a trainset consisting of Tier I passenger equipment demonstrating alternative crashworthiness and occupant protection performance under the requirements of appendix G to this part.
*Trainset, Tier III* means an intercity passenger train that provides service in a shared right-of-way at speeds not exceeding 125 mph and in an exclusive right-of-way without grade crossings at speeds exceeding 125 mph but not exceeding 220 mph.
*Trainset unit* means a trainset segment located between connecting arrangements (articulations).
*Transverse* means in a direction perpendicular to the normal direction of travel.
*Ultimate strength* means the load at which a structural member fractures or ceases to resist any load.
*Uncoupling mechanism* means the arrangement for operating the coupler by any means.
*Underframe* means the lower horizontal support structure of a rail vehicle.
*Unit* means passenger equipment of any type, except a freight locomotive when used to haul a passenger train due to failure of a passenger locomotive.
*Unoccupied volume* means the volume of a rail vehicle or passenger train which does not contain seating and is not normally occupied by passengers or crewmembers.
*Vehicle, rail* means passenger equipment of any type and includes a car, trailer car, locomotive, power car, tender, or similar vehicle. This term does not include a freight locomotive when used to haul a passenger train due to failure of a passenger locomotive.
*Vestibule* means an area of a passenger car that normally does not contain seating, is located adjacent to a side exit door, and is used in passing from a seating area to a side exit door.
*Vestibule door* means a door separating a seating area from a vestibule. End-frame doors and doors separating sleeping compartments or similar private compartments from a passageway are not vestibule doors.
*Witness plate* means a thin foil placed behind a piece of glazing undergoing an impact test. Any material spalled or broken from the back side of the glazing will dent or mark the witness plate.
*Yard* means a system of tracks within defined limits provided for the making up of trains, storing of cars, or other purposes.
*Yard air test* means a train brake system test conducted using a source of compressed air other than a locomotive.
*Yield strength* means the ability of a structural member to resist a change in length caused by a heavy load. Exceeding the yield strength may cause permanent deformation of the member.
[64 FR 25660, May 12, 1999, as amended at 65 FR 41305, July 3, 2000; 67 FR 19989, Apr. 23, 2002; 71 FR 36916, June 28, 2006; 71 FR 61857, Oct. 19, 2006; 73 FR 6400, Feb. 1, 2008; 78 FR 71812, Nov. 29, 2013; 80 FR 76146, Dec. 7, 2015; 83 FR 59218, Nov. 21, 2018]