Patent Publication Number: US-3877384-A

Title: Method and machine for laying railroad ties on a prepared road surface

Description:
United States Patent [1 1 Fearon et al.  
 [ METHOD AND MACHINE FOR LAYING RAILROAD TIES ON A PREPARED ROAD SURFACE [75] Inventors: Joseph G. Fearon; Matt F. Rice,  
 both of Boise, Idaho [73] Assignee: Morrison-Knudsen Company, Boise,  
 Idaho 22 Filed: Dec. 21, 1972 21 Appl. No.: 317,704  
 [52] US. Cl 104/6; 104/9 Primary Examiner-M. Henson Wood, .lr. Assistant Examiner-Richard A. Bertsch Attorney, Agent, or Firm-Seed, Berry, Vernon &amp; Baynham Apr. 15, 1975 [57] ABSTRACT A method and machine are disclosed for dispensing railroad ties, particularly concrete railroad ties, along a prepared roadbed surface for a moving vehicle. The tie laying machine is connected to a trailer carrying the ties. The ties are conveyed from the trailer to the input end of the tie laying machine as needed. The tie laying machine includes a forward carriage shiftable transverse to the direction of travel of the vehicle along the roadbed. The vehicle also includes sensing means sensing an alignment line and control and power means operatively connected to the sensing means to shift the carriage to align the ties held by the machine relative to the alignment line prior to discharge. In operation the carriage shifts to a center location to receive a tie from the infeed conveyor of the machine and then, after receipt of the tie, shifts to an alignment position relative to the alignment line. The tie is then released into a discharge assembly where it is discharged on the prepared roadbed surface at a predetermined spaced interval from the preceding tie.  
 PATENTEDAPR 1 5 I975 suzul-n g JFKGO 11 WU 6. A i 2 m m m RH 8 k fi U. o w m m F U w IUIJ /W/ PATENIEUAPR 1 51975 IMP-3E I I l .i. L  
  METHOD AND MACHINE FOR LAYING RAILROAD TIES ON A PREPARED ROAD SURFACE BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to a method and machine for dispensing railroad ties at regularly-spaced intervals along a prepared roadbed surface.  
 2. Prior Art Relating to the Disclosure The laying of railroad ties has generally been largely a manual operation which is not only costly from a labor standpoint but inefficient and slow. Means for au tomatically laying railroad ties are disclosed in US. Pat. No. 3,701,320, entitled Method and Apparatus for Laying Railroad Ties on a Prepared Roadbed Surface.&#34; The tie laying machine disclosed is one which positions tie plates and spikes in place on a railroad tie and then discharges the ties at regularly spaced intervals on the roadbed surface ready for receiving rails thereon.  
 SUMMARY OF THE INVENTION A tie laying machine is disclosed which accepts ties from a trailer. aligns them transverse to the direction of travel of the machine relative to an alignment line, and discharges them at spaced intervals along the roadbed. The machine includes l conveying means for conveying the ties from the infeed end of the machine to the outfeed end. (2) a shiftable carriage at the outfeed end of the conveyor receiving the ties at predetermined intervals from the conveying means moveable in a transverse direction to the travel of the vehicle, (3) means mounted on the vehicle sensing an alignment line adjacent the roadbed for alignment of the ties relative thereto. (4) power means operatively connected to the shiftable carriage for shifting the carriage, (5) control means responsive to the sensing means and operatively connected to the power means for shifting the carriage relative to the alignment line, and (6) discharge means for receiving an aligned tie and discharging it onto the prepared roadbed surface predetermined a predetemined spaced interval.  
  The primary objects of this invention are to provide a method and machine for laying railroad ties which (I) is efficient, (2) less costly, (3) substantially automated. (4) particularly adapted to the laying of concrete railroad ties, and (5) capable of laying ties in alignment such that the rails can be positioned thereon without further movement of the ties.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an overall perspective view of the tie laying machine and trailer connected thereto;  
  FIG. 1A is a partial view of the guidance mechanism of the tie laying machine;  
  FIG. 2 is a partial enlarged view of the rear wheel of the tie laying machine illustrating means for controlling spacing between the ties dispensed onto the prepared FIG. 6 is a front view of the tie laying machine along section line 6-6 of FIG. 4;  
  FIG. 7 is a partial, vertical cross-sectional view of the tie laying machine of FIG. 5 illustrating the tie aligning mechanism and the tie retarder assembly;  
 FIG. 8 is the hydraulic schematic of the tie laying machine; and  
  FIG. 9 is the electrical schematic of the tie laying machine.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, the tie laying system consists of a trailer 1 carrying a series of ties resting on tiered conveyors feeding the ties to the infeed conveyor of the tie laying machine 2 which accepts the ties from the trailer and conveys them to a shiftable carriage assembly mounted on the forward end of the track laying machine. The ties are aligned relative to an alignment line extending parallel and adjacent the prepared roadbed surface by shifting the carriage transversely either to the right or the left to keep the ties in correct alignment relative to the alignment line. Once the ties have been aligned the ties are released one at a time to a discharge assembly which discharges them onto the prepared roadbed surface at predetermined spaced intervals. The tie laying machine 2 includes a wheeled vehicle having an infeed conveyor therein accepting ties from the trailer and a shiftable carriage assembly 40 mounted on the forward end of the frame of the wheeled vehicle.  
 I. Wheeled Vehicle Referring to FIG. 4, the wheeled vehicle includes a main frame consisting of two parallel, horizontally oriented beams 10 connected by suitable cross braces (not shown). Vertical supports 11 extend upwardly from the forward end of the main frame. A second pair of vertical supports 12 extend upwardly rearwardly of the first pair and are joined by a pair of horizontal supports 13 and cross supports I4 forming a support frame for a platform on which the power means 15 for the unit is located as well as the control station 16 for the operator. The frame of the vehicle is supported on wheels 17 secured to stub axles 18 attached to the frame. Sprockets 19 are secured to the inner face of the front wheels between the wheels and the frame of the vehicle. Drive chains 20, trained about sprockets l9 connect with sprockets 21 driven by a hydraulic motor (not shown), the hydraulic motor powered by the power means 15 of the tie placement machine.  
  An infeed conveyor for ties is mounted on the frame of the wheeled vehicle and extends rearwardly, as illustrated in FIG. 4, from its forward pivot connection. The conveying means includes a conveying frame 22 consisting of parallel frame members connected by suitable cross braces. Shafts 23 and 24 are journalled for rotation at the forward and rear ends, respectively, of the frame members. On the respective shafts are mounted sprockets (front sprocket 25rear sprocket not shown) around which are trained link chains 27 suitable for conveying the ties from the infeed end of the conveyor to the outfeed end thereof adjacent the forward end of the vehicle. The rear of the conveyor is mounted for vertical movement about the forward pivot point (shaft 23) to accept ties from either the upper or lower tiers of ties on the trailer. Power cylinders 28 pivotally attached to the frame 10 on each side of the infeed conveyor, as illustrated in FIG. 4, have their pistons 29 pivotally connected to extensions 30 extending from the parallel frame members of the conveyor frame 22. The infeed conveyor is driven by a hydraulic motor (not shown) by chain 32 trained about sprocket 31 and sprocket 33. The infeed conveyor is manually or automatically adjustable between a lower position for accepting ties from the lower conveyor of the trailer and an upper position, as illustrated in phantom in FIG. 4, for accepting ties from the upper conveyor of the trailer. The ties accepted by the conveyor are conveyed from the infeed end to the outfeed end adjacent the shifting carriage assembly to be described. 2. Tie Hold Assembly The tie hold assembly 80 is best illustrated by FIG. 7 and FIG. 5 and comprises two parallel arms 81 pivotally mounted at their rear ends to cross supports 14 of the platform for the motor, control panel and operator. The arms are connected by a crossmember 82 for stability. On the forward end of each of the arms is a downward bulbous projection 83 which, when the arms are in their normal position illustrated by FIG. 7, extends down far enough to prevent the ties from being discharged from the outfeed end of the infeed conveyor. The forward ends of the arms are supported by respective power cylinders 84 and 85 pivotally connected to the upper cross brace 14 of the support frame. The pistons of each cylinder are pivotally connected to their respective arms 81. The power cylinders are double acting cylinders and, on actuation. pull the arms up a sufficient distance to allow the tie on the outfeed end of the conveyor to free fall onto the roller conveyor of the carriage assembly to be described. Coil springs 86 located rearwardly of the respective power cylinders extend between and are connected to the forward cross support 14 of the tie laying vehicle and the upper surfaces of each arm 81. The coil springs aid the hydraulic cylinders 84 and 85 to quickly force the arms 81 down after a tie is released to prevent the following tie from being discharged, thus allowing one tie at a time to fall onto the roller conveyor of the carriage assembly. 3. Shifting Carriage Assembly Supported at the forward end of the frame of the tie laying vehicle is a shifting carriage assembly capable of shifting traversely in either direction relative to the direction of travel of the tie laying machine to align the tie relative to an alignment line extending parallel and adjacent to the direction of travel of the tie laying machine prior to discharge onto the prepared roadbed. The moveable carriage assembly 40 is best illustrated by FIGS. 5 and 7. The carriage frame includes spaced vertical supports 41 connected by a lower cross brace 42. Extending forwardly from the upper ends of the vertical supports 41 are arms 43 connected at their front ends by cross brace 44 and rear by cross brace 43A. The carriage assembly is supported from the frame of the wheeled vehicle for transverse movement relative to the wheeled vehicle at its upper and lower ends. Extensions 45, from which extend shafts 46, are secured to the rear portions of arms 43. Triangular plates 47 secured to the upper ends of the shafts 46 carry rollers 48 journaled for rotation on suitable shafts, as illustrated in FIG. 5. These rollers travel in guideways 49 mounted on vertical supports 11 of the frame of the tie laying machine. The carriage assembly is supported at its lower end by rollers 50 journaled for rotation between horizontally oriented plates 51 which extend outwardly from the lower ends of the vertical supports 11. The rollers 50 contact the rear surface of cross brace 42 of the carriage assembly and a flange 52 extending outwardly thereof.  
  The carriage assembly is moved transversely in either direction by a pair of power cylinders 53 and 54 secured by supports 55 to the vertical frame supports 11 of the tie placement machine. The ends of the pistons 56 of the cylinders have discs 57 secured thereto which are secured to flanges 58 extending from vertical supports 41 of the carriage assembly. Guide shafts 59 extend between supports 55 and 60 through openings in flanges 58. Sleeves 61 mounted on the supports 55 have rods 62 telescoped therein on each side of the moveable carriage. A diamond shaped shaft 63 extending through vertical supports 11 spans the width of the vehicle and extends outwardly on each side thereof. A sleeve 64 surrounds the shaft 63 between the supports 11. The piston 65 of hydraulic cylinder 66, secured to suport 11, is pivotally secured to the sleeve 64 by a clamp 67 as illustrated by FIG. 6. The underside of the sleeve carries two spaced apart plates 68 and 69. Adjustment of the sleeve along the shaft 63 affects adjustment of the moveable carriage assembly relative to the reference line as will be explained. The plates 68 and 69 are adjusted to contact the arms of limit switches 70 and 71 whose function will be described under the heading Operation. The limit switches are mounted on a fixed vertical plate 72 attached to the rear end of the horizontal support members 73 extending rearwardly from the approximate center of cross brace 43A.  
 A. Roller Conveyor v The roller conveyor is best illustrated by FIGS. 5 and 7 and comprises two parallel conveyor frames 87 having multiple rollers 88 journaled for rotation therein. The roller conveyor extends between an infeed end adjacent the outfeed end of the infeed conveyor of the wheeled vehicle and a tie discharge assembly to be described. The roller conveyor is supported by vertical supports 89 extending downwardly from the carriage support arms 43 and a cross brace 90 extending between the vertical supports 89. Ties released by the tie hold assembly free fall down the length of the roller conveyor and are caught at the end of the roller conveyor by upstanding dogs 91 mounted on the lower ends of L-shaped skids 92. The skids are mounted to pivot about pivot points 93 adjacent cross brace 42. Referring to FIG. 7, the skids 92, in the absence of a tie on the roller conveyor, assume the position shown in solid lines of FIG. 7 due to the action of spring 94 secured between the ends of the L-shaped skids and the cross brace 90. The spring tension may be adjusted by turnbuckles 95 connected between springs 94 and cross brace 90. The skids 92, normally biased upwardly, retard the speed at which the ties, released by the tie hold assembly, free fall down the roller conveyor.  
 B. Tie Alignment Assembly of Carriage Assembly At the terminating end of the roller conveyor is the tie&#39;alignment assembly which aligns the ties held by dogs 91 for acceptance to the tie discharge assembly. The tie alignment assembly includes end plates 96 spaced apart the approximate length of a tie and mounted for pivotal movement to the respective ends of cross brage 97. Rods 98 and 99 extend between the plates and the respective ends of a bell crank I00 mounted approximately midway between the pivot points of each of the end plates 96. A power cylinder 101 attached to cross brace 97 has its piston secured to one end of the bell crank as illustrated by FIG. 5. On extension of the piston the respective plates 96 are pulled into contact with the ends of the tie held by the dogs 91 to align the tie for entry to the tie discharge assembly to be described.  
  The tie held by the dogs 91 is released to fall by gravity into the tie discharge assembly on retraction of the dogs 91 and lowering the skids 92. Referring to FIG. 5, each of the L-shaped skids 92 has a pin 102 projecting inwardly from the inner side surfaces which mates with a hook 103 attached to a shaft 104 journaled for rotation between the respective frames of the roller conveyor. Retraction of the piston of power cylinder 105 pivotally secured to cross brace 42, pivotally attached to shaft 104 retracts the dogs 91 sufficiently to allow the tie to fall by gravity into the tie discharge assembly. C. Tie Discharge Assembly of Carriage Assembly The tie discharge assembly accepts ties after alignment and releases them at predetermined spaced intervals on the&#39;prepared roadbed surface. The tie discharge assembly comprises supports 107 extending downwardly from each end of the forward of cross brace 44. On the respective ends of each of the supports are pivotally mounted L-shaped scoops 108 which. in normal position, grip the ends of a tie. A triangular flange 109 on the front edge of each scoop 108 prevents the tie from falling onto the roadbed. Power cylinders 110 pivotally mounted to each of the downward extending supports 107 have their pistons pivotally attached to the lower edge of each of the scoops 108. On retraction of the piston of the cylinders, the scoops are pulled outwardly to allow the tie held thereby to fall onto the prepared roadbed surface. The scoops are adjusted to ride a few inches above the prepared&#39;roadbed surface illustrated by FIG. 7 so that. on release of the tie, it readily falls to the prepared surface. Limit siwtches I11 and 112 are secured to one of the downward extending supports 107 as illustrated by FIG. 5. The contact arm of the limit switch 111 contacts the leading edge of the tie held in the tie discharge assembly to sense when a tie is deposited in the tie discharge assembly. The contact arm of limit switch 112 contacts pin 113. carried by scoop 108, to sense retraction of the scoops. Spacing between the ties on the roadbed surface is controlled by limit switch 114 (see FIG. 2) mounted on plate 115 held by support arm 116. The support arm 116 also carries wheel 117 rotated by contact with the rear wheel 17 of the tie vehicle. The wheel 17 has an inwardly projecting tab 110 which contacts the arm of limit switch 114 with each revolution causing the scoops of the tie discharge assembly to retract. Support arm 116 is pivotally attached to vertical support 119 to allow raising of wheel 117 out of contact with wheel 17 when the vehicle is being moved from one tie-laying location to another. The wheel 117 may be raised and lowered manually or by a power cylinder activated from the control panel. 4. Guidance Mechanism The guidance mechanism (see FIG. 1A) insures that the ties dropped on the roadbed are in proper transverse alignment with one another so that rails can be laid over the ties without further adjustment. An alignment or reference line 120 (see FIG. 1) is established which extends adjacent the roadbed and parallel to the direction of travel of the tie vehicle. The arm 121 of an on off pendulum control unit 122 rides along the reference line. The pendulum control unit is attached to the end of shaft 63 by support arm 123. The control unit is operatively connected to the power cylinders 66 of shift sleeve 64 the amount necessary to keep the discharged ties in correct alignment relative to the reference line.  
 5. Trailer The trailer carrying a load of ties for the tie placement machine is best illustrated by FIG. 3 and comprises a mainframe supported on multiple wheels 131 conventionally mounted at each end. The trailer includes one or more stacked rows of ties resting on respective conveyors. The trailer of FIGS. 1 and 3 includes a lower conveyor and an upper conveyor. The lower conveyor comprises driven parallel chains 132 trained around respective forward and rear sprockets 133, the sprockets attached to shafts 134 supported by the frame of the trailer. The upper conveyor also comprises parallel chains 135 trained around respective sprockets 136 attached to shafts 137 supported from the frame of the trailer. Both conveyors are driven by separate hydraulic motors (not shown) thru chain drive and sprocket arrangements 138 and 139. Operation of the conveyors is controlled from either the control panel 140 on the side of the trailer or from the main control panel 16 of the tie vehicle. Power for the hydraulic motors is supplied by an internal combustion engine 141. The upper conveyor extends forwardly a distance greater than the lower conveyor to mate with the infeed conveyor of the tie vehicle. as illustrated by FIG. 4. The trailer is coupled to the tie vehicle by conventional coupling means 142.  
 6. Coeration Coordination of the various operations taking place from the input end to the discharge end of the tie laying machine is carried out automatically or manually. Automatic operation of the various assemblies is controlled by suitable located limit switches and servovalves which actuate power cylinders to carry out the various operations. The exact location of the limit switches may be as desired.  
  FIGS. 8 and 9 illustrate, respectively, the electrical and hydraulic schematics for the tie laying machine. Referring to the electrical schematic, activation of the various power cylinders controlling various operations of the tie placement machine is by eight solenoid operated valves. Referring to FIG. 6, these valves may be secured to the crossbrace 14 for convenience. These servo-valves 143 through 149 control, respectively, the hydraulic motors of the trailer conveyors, the power cylinders 53 and 54 controlling transverse shift to the carriage, the power cylinder 106 which trips dogs 91 to let the tie drop into the discharge assembly, power cylinders 110 which actuate the discharge assembly to release a tie onto the roadbed, power cylinder 66 adjusting the position of the carriage relative to the reference line, power cylinder 101 operating the tie alignment assembly and power cylinders (not shown) controlling steering of the vehicle.  
  Referring to FIG. 9, the hydraulic schematic, power means 15, suitably a gasoline engine, drives single fixed displacement hydraulic pumps 150, 151, 152 and 153 and variable displacement pump 154. Pump drives hydraulic motors 156 of the trailer conveyor through four-way servo-controlled. spring-centered valve 143 and quick-disconnect coupling 157. The hydraulic motors 156 can also be operated from power means 141, driving pump 158 through four-way manuallyoperated. spring-centered valve 158. A manually operated valve 160 controls operation of either of the motors 156 for movement of either the lower or upper conveyor of the trailer.  
  Referring to FIG. 9, servo-valve 143 is activated manually through forward-off-reverse switch 161 on the control station 16 when the main manual-off-auto control switch 162 is in the manual position. When switch 162 is in the automatic position of trailer conveyors will not operate until the contacts of limit switches 177, 178 and 181 are closed. These limit switches are normally closed when a tie has been aligned and is discharged to the tie discharge assembly and when the carriage is centered with respect to the wheeled vehicle to receive a tie.  
  The infeed conveyor of the tie placement machine is driven by hydraulic motor 163 from pump 151 through four-way servo-controlled, spring-centered valve 182. The infeed conveyor is manually or automatically controlled in the same manner as the trailer conveyors.  
  Ties process along the infeed conveyor until they contact the projections 83 of the tie-hold assembly 80 (FIG. 7 The shifting carriage returns to the center position when limit switch 111 closes indicating discharge of a tie from the tie discharge assembly to accept a tie from the infeed conveyor of the wheeled vehicle onto the roller conveyor of the carriage. If the carriage is not centered with respect to the tie to be received limit switch 180 suitably located energizes one of the solenoids 1441: or l44b of four-way solenoid-controlled, spring-centered valve 144 to center the carriage for receipt of a tie from the infeed conveyor onto the roller conveyor. The ties are released manually from the control station 16 by the operation, one at a time. onto the roller conveyor by retraction of the pistons of power cylinders 84 through shifting of four-way manuallycontrolled, spring-centered valve 164.  
  The tie rolling down the roller conveyor trips the contact arm of limit switch 165 to close the circuit to time-delay relay 166. When the contacts of relay 166 close, the solenoid 148a of two-way servo-controlled valve 148 is activated to operate power cylinder 101 and retract the piston thereof to align the tie for entry into the discharge assembly. Simultaneously, the carriage is shifted right or left by power cylinders 53 and 54, depending on whether the contacts of limit switch 70 or 71 are closed to activate the respective solenoids 144a and l44b of four-way servo-controlled, springcentered valve 144. At the same time, a second timedelay relay 167 is activated. The contacts 167a of relay 167 are set to close after relay 166 to activate the solenoid 145b of fourway servo-controlled, springcentered valve 145, operating power cylinder 105 to retract dogs 91 and allow the tie to fall into the discharge assembly, provided that the contacts of limit switches 111 and 112 indicate the tie discharge assemblly is empty and the scoops 108 are in position to receive a tie.  
  The tie held by the discharge assembly is discharged onto the prepared roadbed surface by operation of limit switch 114 (FIG. 2) which, when tripped, activates the solenoid l46b of four-way servo-controlled, spring-centered valve 146, operating power cylinders 110 to retract scoops 108, allowing the tie to fall onto the roadbed. A manual cut-out switch 168 is provided to prevent operation of the discharge assembly when moving the tie vehicle from one laying operation to another.  
  Adjustment of the carriage assembly to the correct transverse position relative to the reference line is accomplished through the pendulum control unit 112, as described. Pendulum switch 169 swings between two positions to trigger either time-delay relay 170 or 171 to activate either solenoid 1470 or 147b, which actuate power cylinder 66 to move sleeve 64 right or left to recenter the pendulum arm relative to the reference to the reference line.  
  The vehicle is steered to the right or left by a joy stick 172 which activates, depending on the set of contacts closed, solenoids 148a and 148b of four-way servocontrolled operating power cylinder 173 connected to the forward wheels of the tie vehicle. The infeed conveyor of the vehicle is raised or lowered manually by activation of the solenoids of four-way, manuallycontrolled. spring-centered valve 174 operating power cylinders 28.  
 The travel hydraulic system of the tie machine is il- 35 lustrated by FIG. 8 and is supplied with power from variable pump 154 which supplies power to rotary fixed displacement motors 175 and 176.  
  The embodiments of the invention in which a particular property or privilege is claimed are defined as follows:  
  1. A machine for aligning and dispensing railroad ties along a roadbed surface to an established reference line extending along the length of the roadbed surface. comprising:  
  a vehicle supporting railroad ties thereon adapted for travel along a roadbed surface along which a reference line extends,  
 sensing means for sensing the position of the vehicle relative to the established reference line,  
 a shifting carriage assembly having an infeed and an outfeed end for receiving and discharging ties, the shifting carriage assembly supported by the vehicle for movement transverse to the direction of travel of the vehicle from a receiving position wherein ties are received from the vehicle to an alignment position relative to the established reference line for discharge of ties aligned with respect to therefment position for discharge of ties one at a time responsive to the sensing means and the established reference line. I 2. The machine of claim 1 wherein the vehicle includes an infeed conveyor having its outfeed end disposed adjacent the infeed end of the shifting carriage assembly.  
  3. The machine of claim 2 wherein the carriage assembly includes alignment means mounted thereon receiving ties one at a time from the infeed conveyor and aligning them transversely for receipt by the discharge means.  
  4. The machine ofclaim 3 including tie release means adjacent the outfeed end of the infeed conveyor releasing the ties one at a time from the infeed conveyor into the carriage assembly.  
  5. The machine of claim 3 wherein the discharge means includes (1) tie holding means mounted on the carriage assembly downstream from the alignment means for receiving and holding the aligned ties, (2) power means connected to the tie holding means for releasing the ties at predetermined intervals, and (3) control means sensing the forward travel of the wheeled vehicle and actuating the power means to drop the ties held by the tie holding means at predetermined spaced intervals.  
  6. The machine of claim.3 wherein the alignment means includes (1) members contacting the respective butt ends of the tie on the carriage assembly to move the tie transversely and correct its alignment for entry into the discharge means, (2) power means operating the alignment means, and (3) control means sensing the alignment position of the tie and actuating the power means to correctly align the tie.  
  7. The machine of claim 2 wherein the control means initially shifts the carriage assembly to the receiving position for receipt of a tie from the infeed conveyor of the vehicle. then shifts the carriage transversely relative to the vehicle to the alignment position for discharge of the tie relative to the reference line.  
  8. A method of positioning and dispensing railroad ties from a tie laying vehicle in aligned. spaced relation along a roadbed surface for receipt of rails thereon, comprising:  
 extending a reference line along the roadbed surface on which the ties are to be discharged, v conveying individual railroad ties in spaced relation to one another to a shifting carriageassembly of the tie laying vehicle which shifts laterally relative to the direction of travel of the tie laying vehicle, sensing the position of the vehicle relative to the ref- 5 erence line,  
 aligning the ties held by the carriage assembly by lateral shift thereof with respect to the sensed position of the reference line, and discharging the ties from the carriage assembly onto the roadbed surface at predetermined spaced intervals relative to increments of forward travel of the vehicle.  
 9. A method of positioning and dispensing railroad ties from a tie laying vehicle in aligned, spaced relation along a roadbed surface for receipt of rails thereon,  
 comprising:  
 providing a reference-line extending essentially parallel to the length direction of the roadbed surface,  
 conveying ties to a tie laying vehicle traveling along the roadbed surface having a laterally shifting carriage assembly thereonwhich shifts laterally relative to the direction of travel of the tie laying vehicle,  
 conveying a tie into the shifting carriage assembly of 35 the tie laying vehicle.  
 sensing the position of the tie laying vehicle relative to the reference line,  
 shifting the carriage assembly laterally relative to the tie laying vehicle and the sensed position of the refe rence line to an alignment position for discharge of the tie onto the roadbed.  
 sensing the movement of the forward tie laying vehicle along the roadbed. and discharging the aligned tie at a predetermined spaced interval from the preceding tie onto the roadbed relative to a predetermined increment of forward travel of the vehicle.