US1174023A - Railway signaling device. - Google Patents

Railway signaling device. Download PDF

Info

Publication number
US1174023A
US1174023A US4101815A US4101815A US1174023A US 1174023 A US1174023 A US 1174023A US 4101815 A US4101815 A US 4101815A US 4101815 A US4101815 A US 4101815A US 1174023 A US1174023 A US 1174023A
Authority
US
United States
Prior art keywords
train
trip
pawl
block
track
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US4101815A
Inventor
Herbert Russell Nevens
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEVENS-WALLACE TRAIN CONTROL Co
NEVENS WALLACE TRAIN CONTROL Co
Original Assignee
NEVENS WALLACE TRAIN CONTROL Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NEVENS WALLACE TRAIN CONTROL Co filed Critical NEVENS WALLACE TRAIN CONTROL Co
Priority to US4101815A priority Critical patent/US1174023A/en
Application granted granted Critical
Publication of US1174023A publication Critical patent/US1174023A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B61RAILWAYS
    • B61LGUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
    • B61L3/00Devices along the route for controlling devices on the vehicle or vehicle train, e.g. to release brake, to operate a warning signal
    • B61L3/02Devices along the route for controlling devices on the vehicle or vehicle train, e.g. to release brake, to operate a warning signal at selected places along the route, e.g. intermittent control simultaneous mechanical and electrical control
    • B61L3/08Devices along the route for controlling devices on the vehicle or vehicle train, e.g. to release brake, to operate a warning signal at selected places along the route, e.g. intermittent control simultaneous mechanical and electrical control controlling electrically

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Train Traffic Observation, Control, And Security (AREA)

Description

H. R. NEVENS.
RAILWAY SIGNALING DEVICE.
A'PPLycATxoN HLEUAPR.1B,1913. RENEwED JULY 20,1915.
1,174,023. Patented Feb.29,1916.
3 SHEETS-SHEET 2.
hj I l /4 HerZeZRNevems,
H. RQ NEv'ENs.
RAILWAY SIGNALING DEVICE.
APPLICATION FILED APR. I8, 1913. RENEWED JULY 20| 191.5- 1,174,023. Patented Feb. 29,1916.
3 SHEETS-SHEET l.
'rl-1E COLUMBIA PLANDQRAPH nu.. WASHINGTON, D. c'.
H. R. NEVENS.
RAILWAY SIGNALING DEVICE.
vAPPLICATION FILED APR.18,1913. RENEWED JULY 2o, 191;l
1,174,023, Patented Feb. 29,1916.
3 SHEETS-SHEET 3.
ZZ l Z' lli/f 4M A j?? 9' 48 THE COLUMBIA PLANOGRAPH co., WSHINGTON. D. C.
'entran sfrafrns f iricn RAILWAY SIGNALINGDEVICE.
introns.
'Specification of Letters atent.
Patenten rei); es, isis.
Application filedlpil 18, 1913,'Sera1 No. 761,902. Renewed .Tuly 20, 1915. SeralNo 41,018.k
To all whom it may concern Be it known that l, l'lfnnBnR'r-R. NnvENs,
a citizen of the United States, residing at Hartford countT oi Hartford State of Connecticut, have invented certain new and useful' linprovenients in i Railway Signalingv Devices, of 'whichthe following is a specification. l Y
rlhis invention relates to the positive control of railroad trains and the like, for the purpose of preventingthe neglect ordisobedience of the usual signals employed in such systems. y r
The'invent'ion is particularly 4adapted to be rused in block systems Where trainsy are to be kept absolutely rwithin certain block limits.
The present inifention is an amplification of the principles setorthin severalprior applications entrain controlling mechanism tiled by me, and consists chiefly in variousv a train traveling in the directiony of the current of trallic and is ineli'ective when struck at the same time, set the blockinadvance to f protect its her-.d end, in the event that a train should be approaching in the opposite direction.k lt is necessary, therefore, on
Vsinge track roads that atripper be disposed at each end of a block and on opposite sides of the track so as to control both directions oii travel. Thesepawls Vpoint in oppof site directions, that is to say, the paWl at the right side ofthe tracln'on whichy side `the brake setting mechanism of the engine is carried, and the signal arnis of the block system are disposed, is pointiiigtoward the currentrof traliic and in the direction of approach ci: the train, and the pawl at the left side of the trackis pointingtoward a train approaching from the opposite direction or against the current of trailic.k The use of a pawl effective in one direction and ineiiective inthe other overcomesthe habil# ity of a train stopping itself on a clearv block when passing the pawl on the left side of the track or in passing the rear side of a signalfarinon the left of the'track.V This arrangement is especially desirable in yplaces where tratlic is congested and the stops must be close together to allow the vbacking of trains against the current of trah'icby signal.y lt, moreover, obviates the use of a divide in the track circuit. v v l ."Considering briefly the :double track installation. l'ln this form the signal box is always on the right side'of the track at the "entrance to a blockand thereis no box on the left side of the track at the eXitrom 4the block. ln'the event that a reverse movenient is desired, the trains are lnecessarily `run against the `currentoi' .traffic` and there .is virtually nosignal'control. y ithereore,` pass the pawl 'Without being stopped. Should itbe foundnecessary or desirable', however, it is alwayspossible to installa signal boX at each` end ofa desired Zblock ,onopposite' sides ofthe track as in the single track installation;
f rEhe construction and principle of v,my invention will Ybe more fully disclosed in the specification which follows and as illustrarlhey will,
tive of thek same Iliave shown in-thegaccom- Y the'purpose's intended.' n r n Throughout ,the yspecification and drawings like characters of reference are ein` Fig. Bis asimilar View showing the'pawl "depressed into non-interfering position.
'lpanying drawings anembodiment which I have lfound practical and well adapted for ployedto indicate corresponding partsand l Fig. 4 is a plan view of one of the boxes with the cover removed to show its detailed construction. Fig. 5 is a longitudinal section on the line .5*5 of Fig. 4, the pawl being in non-interfering position. Fig. 6 is a section at right angles to Fig.- 5, the pawl being shown in interferingposition. Fig. 7 is a detail of the pawl. Fig. 8 is a vertical section on the line 8-8 of F ig. 7 and Fig. 9 is a detail section of a slightly modified construction of pawl.
For the purposes of explanation I have illustrated five sections or blocks of track lettered A, B, C, D, E, in Fig. 1. These blocks are insulated from each other at a, b, c, (l, and on account of the limited space are shown very short although it will be understood that each section is intended to represent a block of more than a train length in extent. It will also be understood that I place a signal box at the entrance and exit of each block and on opposite sides of the track in a single track installation, although only two boxes are here shown on accountof the limited space and the necessity for ladequately illustrating the wiring of the respective blocks. y
At the right hand side of the track, near the entrance to the block B', I mount my tripping mechanism which may be supported on two ties T. A similar mechanism is of course mounted on ythe opposite side of the track at the exit of said block. This tripping mechanism comprises in the preferred embodiment a tripping pawl 1 disposedn adjacent to the rail and within the operative influence of the train wheels. T his pawl is approximately right triangular in shape and has its inclined face or hypotenuse 2 disposed so as to be rigid when struck by the wheel of a train traveling against the current of traffic, and its leg 3 set vertically with respect to the ties and yieldable whenlstruck by the wheel of a train traveling with the current of traffic. The lower portion el of said pawl is formed as a weighted counterbalance to cause the pawl tcright itself after being struck. Said pawl is mounted upon the wrist pin 5 of a rocker arm 6 which arm is chambered to receive the inner end of said pin. Arranged in said chamber and rigid on said Wrist pin is a segmental rack 7 the teeth of which are adapted for engagement with the teeth of a rack rod 8 mounted in said chamber and normally held in extended positionby a coil spring` 9 mounted in a bore in the rocker arm 6. Vhen the inclined face 2 of the pawl is struck a practically rigid surface will be presentedto the wheel, a slight play being of course allowed to prevent stripping of gear teeth. W'hen'the vertical face 3 is struck the pawl will yield, the rotation thereof forcing the. rack rod back against or housing 1:2 having its cover hinged at 13 and adapted to be locked at 14 by an ordinary padlock. Inclosed in said housing and pivoted on said shaft is a depending link 15, the free end of which is bifurcated to provide ears 16 adapted to lit over the longitudinally movable block 17, which block is chamfered on each side to form shoulders adapted to confine the ears of the link and act as stops or abutments to prevent the disengagement of the link from the block. Threaded in said block at its inner end is a short stem 18 the opposite end of which is slidable in the bore of a bearing 19 threaded in to a boss 20 projecting horizontally from the housing. A. spring 21 surrounds said stem and is confined between the bearing 19 and the end of the block. Said spring is normally under compression, that is, when the pawl is in interfering position the block will be forcing the stem into the'bore of the bearing 19 and thereby compressing the spring. 1n the opposite end of the block is threaded the inner end of a long stem 22 axially alining with said short stem 18 and carrying a lock nut :23 on its inner end. The outer end of said stem is slidable in the bore of a bearing 24 threaded into a boss 25 projecting horizontally from the housing and is controlled by a spiral spring 2G coiled thereabout and confined between the inner end of the bearing and trie nut 23. The block 17 is therefore in the nature of a turn buckle and permits a relative adjustment of the stems 18 and 22, while the tension of the spring 26 may be regulated by screwing up on the lock nut 2B. The threaded bearing plugs 19 and 2st also permit relative outside adjustment of the parts.
Fastened to the rock shaft to move with the movement thereof are the arms 27 of a yoke shaped frame, the free ends of which are joined by a weighted arm 28 normally holding the pawl in the position illustrated in Fig. 2, and when in this position restingl on a buffer 29 supported on the housing.
With the parts in the position shown in Fig. 2 the tendency of the pawl would be to operate the brake system of the train irrespective of the condition of the track, 'z'. e.
whether it was safe or unsafe for the pas-l sage of the train. lnasmuch as it is not desirable to have this tripper effective unless there is already a train inthe block C, I therefore provide a holding mechanism for maintaining the trip in the depressed position shown in Fig. 3 when the block C is unoccupied, which locking mechanism is automatically released by the exit of the train from the block B into yblock C to return the trip to interfering position and protect the rear end of the train. This locking mechanism comprisesy a pair of magnets 30 supported on brackets 31 rising from the floor of the housing. The adjustment of these magnets is had by meansof a pair ofmilled nuts 32 threaded into a post 33 adjustable relative to said magnets. The magnets are wired up in a normally closed electrical circuit and are always energized it 'there is no train in the block C. An armature 34 is carried on the lower end of a vertically disposed lever 35 ypivoted at 36 in brackets 37.
.Inasmuch as the magnets are normally energized, the lever 35 is held in the vertical p0- sition shown in Fig. 3. ln this position the notch 3S oit' said lever is disposed so as to be engaged by a shoulder 39 on the cross arm 23 whenever said cross arm is raised sulii-v wheel the yoke arms 27 are raised, lifting Y the cross arm 23 tothe level of the notch 33. nasmuch as the lever 35 is already in position to support the cross arm when said arm is raised, the notch 38 catches theedge 39 of the cross arm to lock it in raised position. l/Vhen the cross arm is locked the pawl will be held in the depressed position shown inV Fig. 3 as long as the magnets remain energized. The magnets are connected in cir-V cuit with the rails of the section C. A simpler electrical circuit (see Fig. 1) comprises lead wires 40 and 41 leading from the windings of the magnets to each of the rails of the block C. Also connected to said rails are the lead-wires 42 and 43 of a battery 44.
1n Fig. 9 1 have shown a slightlyfmodilied construction of pawl. '1n place of the toothed segment 7 l mount on the stud 5 a toothed disk 45, the teeth of which are adapted for engagement with the teeth of a pair of rack rods 46 and 47 arranged'in superimposed relation to each other and on opposite sides of the disk. y Said rack rods are held in their normal position by a pair of coil springs 48 and 49 respectively, said springs being of different stiffness. 1n the operation of this form of pawl a train striking the inclinedv face 2 thereof unlike the type shown in FiO. 7, will slide thek rack rods longitudinally against their springs. The
yor against the current of traffic.
spring 48 "againstvwhich the upper rack rod 46 bears, is ,stiff enough to set the tripper `,carried by the engine and thus apply the brakes. l/Vhen'a train coming from the opposite direction strikes the vertical face 3 of the pavvl, the pawl will yield to the impact only serves to returnthe pawlto its normal Vposition after each fimpact. y1t is here desirable to statejthat vthe weight on the pawl fandthe long'arm inthe box will throw the trip into danger of stopping position should any'of the springsbreak. y p
The operation is substantially asv follows.:
ing inthe direction or' approach of the train and is inposition to be influenced by the wheels.y l/Vhen the block C is clear, "the magnets ywill be included inl the circuit through the track battery and rails of said' yblock and will therefore beenergized to hold `the locking VVlever up in position to be engaged by the cross web 39 of the yWeighted yoke 27. The first wheel of a train entering the block B depresses the pawl against the action of the vspring Q6 and rocks the cross arm 28 up suiiciently to engage its web 39,
with the notch 38 of" the lever 35. This locks the pawl in kdepressed position so as not' to contact with the tripper of the brake setting mechanism vcarried by the train. The pawl remains in depressed position until the train has passed into the block C whereupon the'magnets will be cut'cut by The normal position of the parts is that .c
shown in Fig. 2 in which kthe pawl is pointreason of-the wheels and aile bridging the currentacross the rails of said block. The denergization of the magnets releases the armature'34 and thelever 35 drops by gravity. The support for the cross arm 28 being thus removed the weight drops, raising the arm 6 and bringing the pawl yup into interfering position so as to protect the train now in the block C against rear-end collision. As soon as the train in block C passes out of said block, the circuit through the Vmagnets is .restablished and the magnets areagain energized. This puts the lever 35 in condition to support theweight 29 when'said weight is again raised. The pawl at the exit of the block (on the left hand side 'of the track) is always in interfering position relative to the wheels but will yield to the impact by reason or" its toothed segment andmovable rack rod, its yspring serving to return it to interfering position after each actuation. The pawl is therefore obviouslyvV incapable of interference except to a train entering from the opposite direction This protects the train from a head on collision.
Should block C already be occupied by a (it being of course impossible under ordinary conditions for a train to enter said block past the eXit covering pawl against the current o f traliic) any train approaching block C will, therefore, find the ent-rance covering paivl in interfering position so that when a wheel contacts With it, said pavvl Will be depressed by the Wheel but Will rise again immediately behind the Wheel to trip the brake setting mechanism carried by the engine. This tripping mechanism for setting the brakes and stopping the train may be of any desired construction as that set forth in the application filed by me J une 19, 1911,lserially numbered 634,010. It is oloviously impossible for the locking lever to engage the notch of the yoke and lock the paWl in depressed position -when the block Gis occupied, since the magnets are denergized and the spring 26 is exertingits tension to urge the pawl back to its interfering position. lhe train will, therefore, be stopped at the entrance to said block.
It Will thus be seen that my device constitutes a positive stop for a train approaching .a block already occupiedkor in which the circuit is broken through an accident to the rails and that not only is the rear end of the train protected, but provision is made for preventing the entrance in the block of a train approaching from the opposite direction.
Various modifications in the construction and form of my invention coming Within its scope andv spirit, may obviously be resorted to if found Within the limits of the appended claims. y
lNhat l, therefore, claim and desire to secure by Letters Patent is: Y'
1. ln a tripping mechanism, a tripper, a gravity operating member therefor, a gravity lock normally disposed in the path of said member in supporting relation thereto, and independent electrically controlled means having an engaging relation with said lock effective to Vmove said lock into position` tor support said gravity member and having a disengaging relation with said lock effective to allow said lock to fall by gravity out of supporting position relative to said gravity operating member.
2. ln train control mechanism, insulated track sections, a trip in each section normally positioned in interfering relation to the kWheels of a passing train, a normally closed electrical circuit establishing communication between a trip and yan adjacent'track section, means included in said circuit normally effective to lock said tripin non-interfering position after contact of the first train Wheel with said trip, and means to return the trip to interfering position when the circuit to said locking means has been broken by the passage of the train past said trip and into said adjacent section.
ES. In a tripping mechanism, a pivoted tripper, a gravity member operatively connected with said tripper, and effective to maintain said tripper in actuating position, a pivotal support for said gravity member having a supporting yand a non-supporting position and normally disposed in the path of said gravity member to support the same, `an armature carried by said pivotal support, and an electro-magnet associated with said armature and having a normal engaging relation with said armature, effective to maintain said pivotal support in its supporting position relative to said gravity member and having a disengaging relation with said armature effective to allow said support to assume its non-supporting position relative lto said gravity member.
4L. ln a tripping mechanism, a tripper, a Weighted operating member therefor, a gravity lock for said member normally disposed in the pat-li of said operating member and in supporting relation thereto, an armature movable with said lock and an electromagnet associated with said lock and having a normal engaging relation with said armature eifective to maintain said lock in position to support said operating member and having a disengaging relation With said armature eiijective to allovv said lock to fall by gravity out of supporting position relative to said operating member.
5. In a tripping mechanism, a pivoted tripper, an actuating counterweight operatively connected with said tripper' and effective to maintain said tripper in actuating position, a pivotal support for said counter-Weight having a supporting and a non-supporting position and normally disposed in'the path of said counter-weight to support the same, an armature movable with said pivotal support, and means having an engaging relation with said armature effective to move said support into its countervveight supportive position and having disengaging relation with said armature effective to alloiv said pivotal support to fall by gravity into its non-supporting position relative to the counteriveight.
6. 1n train control mechanism, a trip actuating member normally positioned in interfering relation to the Wheels yof a passing` train and arranged to be displaced by Vcontact with the lirst train Wheel from` its position ofinterference to one of non-interference, a locking mechanism normally effective to lock said member non-interfering position immediately after its displacement by the lirst train Wheel and ineffective to lock said member in non-interfering position when it is desired to stop the train,
tion as soon as the train passes beyond the limits of said control.
i'. 1n train control mechanism, insulated track sections, a trip normally positioned in interfering relation to the ivlieels of a passing train, a rock shaft operatively connected with said trip, means associated with said shaft normally effective to assist in maintaining said trip in interfering position, including a gravity operating member, a locking member positioned for engagement with said gravity operating'member, an armature movable with said locking member, an electro-magnet associated with said armature, and a normally closed electrical circuit fi'om said magnet to an adjacent track section and normally effective to put said locking member in condition to lock said gravity operating member and maintain the trip in non-interfering position after contact of the first train Wheel with said trip.
8. 1n a train control mechanism, insulated track sections, a trip normally positioned in interfering relation to the Wheels of a passing train, rock shaft operatively connected with said trip, a gravity operating member, normally effective to assist in maintaining said trip in interfering positionfa pivotal support for said member having a supporting and a non-supporting position vand normally disposed in the path of said gravity member, and a control for said pivotal support e'ective to move said support into position to support said gravity member when it is not desired to stop a train and effective to permit said pivotal support to assume its non-supporting position relative to the gravity member when it is desired to stop a train.
9. 1n train control mechanism, insulated track sections, a trip normally disposed in interfering relation to the Wheels of a passing train and arranged to be displaced from its position of interference to one of noninterference by contact with the first train Wheel, a gravity operating member` associated with said trip, a pivotal support for said member having asupportiiig position effective to engage said gravity member and lock the trip in non-interfering position iinmediatcly after contact of the first Wheel With the trip and having a non-supporting position inedective to lock the trip, A and an electrical control for said pivotal support normally effective to move said support to its supporting position.
10. In train control mechanism, track sections, a trip normally disposed in interfering relation to the wheels of a passing train, a rock shaft operatively connected with said` trip, a pairof spring controlled -stems operatively connected With said shaft.
a balance member connected with said shaft, a locking member positionedfor locking engagement with said balance, andan electrical circuit controlling said locking member and normally effectiveto move saidv locking .member into.` position 'to lock said balance c member after contact ofthe irsttrain Wheel with the trip. n 11.1ntrain control mechanism a trip, a rock shaftfoperatively connected With said trip, a link on Said Shaft, a pair of stems` connected with said link, springs of differposition of interference to one of non- `interference, and means i becoming effective upon the displacement of said track tripper Vto positively maintain said trip in non-interfering position to permit the unobstructed passage of the train carried tripper past said track trip. i
18. 1n train control mechanism an insulated track section, a track trip mounted in said section for contact with the tripper of a train carried brake-setting mechanism, means normally eective to maintain said tracktrip in interfering relation to the Wheels of a train passing through said section, said means being overcome by the displacement c of said track trip by ythe-first train Wheel from its position of interference to one of non-interference, and gravity operating electrically controlled means becoming effective upon the displacement of said track trip to positively maintain Said trip inl noniiiterfering position as long as the train is in said section to permit the unobstructed passage of the train carried trip past said track trip and ineffective to lock said track trip in non-interfering position When it is desired to stop a train.
14. 11n train control mechanism, insulated track sections, a track trip in one of said sectionsmounted for contact with the tripper of a train carried brake-setting mechay nisin and normally disposed in interfering relation to thev Wheels of a passing train and normally displaceable from said position of interference to one of non-interference by the first train Wheel to permit the unobstructed passage ofthe train carried' tripper therepast, and means effective When it is desired to stop the train to positively maintain the traek trip in Wheel interfering and tripper contacting position whereby the track trip is displaced by the first train Wheel and returns yimmediately behind the Wheel to zictuate the train carried tripper.
In testimony whereof I afiiX my signature in presence of tWo Witnesses.
HERBERT RUSSELL NEVENS.
Witnesses i GEORGE B. RAWLINGS, IDA S. CLEMENT.
Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents,
Washington, D. C.
US4101815A 1915-07-20 1915-07-20 Railway signaling device. Expired - Lifetime US1174023A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US4101815A US1174023A (en) 1915-07-20 1915-07-20 Railway signaling device.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US4101815A US1174023A (en) 1915-07-20 1915-07-20 Railway signaling device.

Publications (1)

Publication Number Publication Date
US1174023A true US1174023A (en) 1916-02-29

Family

ID=3242025

Family Applications (1)

Application Number Title Priority Date Filing Date
US4101815A Expired - Lifetime US1174023A (en) 1915-07-20 1915-07-20 Railway signaling device.

Country Status (1)

Country Link
US (1) US1174023A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8061662B1 (en) * 2010-02-09 2011-11-22 Bartek Peter M Portable automatic train trip cock tripper

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8061662B1 (en) * 2010-02-09 2011-11-22 Bartek Peter M Portable automatic train trip cock tripper

Similar Documents

Publication Publication Date Title
US1174023A (en) Railway signaling device.
US1174024A (en) Train-stop mechanism.
US1187586A (en) Electric railway-signal and appertaining mechanism.
US853126A (en) Rail-spread-indicating device.
US1259259A (en) Automatic railroad-switch.
US1527109A (en) Railway safe-running device
US1349986A (en) Train-operated railway-gate
US912786A (en) Electric signal system.
US1702150A (en) Automatic crossing block for railways
US633892A (en) Railway-signal.
US1980084A (en) Power-operated lock for spring switches
US1862276A (en) Railway crossing guard
US1123284A (en) Derailment-guard.
US1186750A (en) Automatic signaling and train-stopping device.
US1190617A (en) Device for preventing collisions between railway-trains.
US856849A (en) Automatic railway-signal.
US1517784A (en) Automatic railway-crossing signal
US765380A (en) Railroad safety appliance.
US1189455A (en) Signal device.
US1084610A (en) Railway signaling system.
US1374828A (en) Railroad-crossing gate
US773415A (en) Signaling system for railways.
US1241454A (en) Automatic train control.
US1369062A (en) Ramp contact device
US1082095A (en) Train control and signal system for double-track railways.