631

The new NX control machine is located in the operator's office in the Windsor station New at Windsor, ·Ont. ,

Lever-control plants, with On the Michigan Central mechanical locking, re­ placed by modern NX entrance-exit and minia­ tracks north of the north platform, freight trains are pulled from Detroit ture-lever all-relay plants and in such instances these trains are by electric locomotives, and then routed to and from the main line at routed over crossover No. 5 and tum­ the turnouts and crossovers west of out switch 11 to the freight and the platform. then into the Electric Yard. From AT Windsor, Ont., at the east end of In order to permit a track crew to this yard, steam locomotives pull the the double-track tunnels under the work on one track or the other in­ trains through Tower 3 interlocking Detroit River, the Michigan Central side the tunnels, the track layout at to the freight or out Lines in Canada has extensive facili­ Windsor and the signaling were de­ onto the main line eastward. Likewise, ties including three main-line cross­ signed to permit trains to be operated westbound freight trains are pulled overs, turnouts from the double-track in either direction on either track into the Electric Yard by steam loco­ main line to the freight yards, and · through the tunnels, traffic-locking motives, and then electric locomotives special sidings to facilitate changing for the control of the signals being pull the ·trains through Windsor and from steam to electric locomotives. provided as will be explained later. to Detroit. An additional handicap The Michigan Central operates 25 Another important phase of the in the operations is that all passenger passenger trains and approximately operations at Windsor is the necessity trains stop at Windsor while customs 43 freight trains daily through Wind­ for changing locomotives. Electric and immigration inspections are made. sor. Also, 6 passenger trains of the locomotives are used on the 2.7 -mile The duration of the inspections on a Canadian Pacific are operated daily territory through the tunnels between certain train cannot be determined in on the Michigan Central between Windsor and Detroit, and steam loco­ advance, and if the delay is too long, Windsor and. Detroit. The line of the motives are used on the territory east other trains may have to be run Canadian Pacific from Toronto, Ont., of Windsor. The locomotives fo~ pas­ around. Therefore, crossover arrange­ comes in at the northeast portion of senger trains are changed wh;ile the ments are provided to permit such the Windsor layout and connects with trains are standing at the station plat­ moves. the track along the north side of the forms. The and switches west At the time the tunnels were com­ west end of the Electric Yard. When of the platforms are used for changing pleted in 1907, two General Railway using the main line tracks for station locomotives on westbound trains,· and Signal Company lever-control electric stops at Windsor, these Canadian the special locomotive siding east of interlockings were installed at Wind­ Pacific passenger trains are routed signal 30 is used when changing loco­ sor to handle the switches and signals. through the lead between the yard and motives on eastward trains. N umer­ Tower 1, which handled the area from the main line east of signals 30 and ous extra lineups of the interlocking the east end of the tunnel to Windsor 32. When the main tracks at the sta­ are required to get the locomotive on station, had 33 working levers to con­ tion are occupied, the Canadian and off these sidings, and off and on trol 5 switches, 5 crossovers, 1 , Pacific trains use the two freight the passenger trains. Eastbound and 20 signals, and 2 check lock: levers. RAILWAY SIGNALING November, 1940 632 Starting near the west end of the cuit controllers, signal-repeater relays be controlled by one man rather than Windsor layout the tracks descend to­ and a set of knife-switch levers in part by each of two men. On the ward the tunnels on a 1.5 per cent mounted on a panel in the switch­ other hand, the routing of freight grade. In view of the fact that some tender's house. Not only bec·ause of trains into and out of the west end car might get away and drift back the damage done by the fire at the in­ of the Electric Yard had to be co­ toward the tunnels, a Wharton type terlocking Tower 1, but also due to ordinated with the operation of the derail was installed on the eastward the fact that the old plants needed ex­ east end of this yard which was han­ track just east of the eastward home tensive replacements, a decision was dled by the interlocking Tower 3. signal. To provide derail protection for the westward track a switch, which was removed during recent track changes, was set normally for View looking west the turnout. Tower 2, which con­ with signal 9 at the right and sig­ trolled the area east of the station nal 12 at the left including the leads to the yard, had 38 working levers to control 14 switches, 2 crossovers and 22 signals. A me­ chanical interlocking, Tower 3, was installed at the east end of the Electric

The logical solution, therefore, was to provide an entirely different arrange­ ment of interlocking control limits, and to use modern interlocking con­ View looking east trol machines and systems of circuits. with signal 4 at the right and sig­ nal 6 at the left New Interlocking Limits A new NX interlocking machine, in the office of the station at Windsor, now controls the switches, and signals formerly included in the Yard to control the switches and sig­ made to reconstruct the interlockings Tower 1 interlocking, and also the nals at that layout. throughout Windsor, and provide main line crossovers, locomotive in­ In August, 1939, the 600-volt d-e. modern types of control machines. terchange track switches, and turn­ traction circuit was accidentally con­ outs leading to the yard, which were nected to some of the interlocking cir­ An Analysis of Operations formerly included in Tower 2 inter­ cuits, and the control machine, wiring locking. The remaining switches and An analysis of the operations signals at the west end of the Electric showed that the handling of trains Yard, which were formerly in Tower through the passenger station area, 2 interlocking, are now controlled including the changi~g of locomotives from a miniature-lever interlocking machine in Tower 3 at the east end of the Electric Yard. The upper story of the old Tower 1 was removed, and the lower story was rehabilitated as a

and accessory apparatus in Tower 1 were seriously damaged, so that the plant was out of service. As a tem­ porary measure, hand-throw switch stands were installed to operate the on passenger trains, as well as the switches, and the signals for direct­ routing of freight trains off or onto ing routes were controlled by circuits the main line, all fell in one operating properly selected through switch cir- category, and, therefore, might better Track and signal plan of the entire NovemiDer, 1940 RAILWAY SI G NALING 633 one-story building for housing switch­ which would authorize train move­ moves on a route over a crossover to ing apparatus for the electric traction ments at the highest possible speeds the

interlocking ·layout at Windsor 634 RAILWAY SIGNALING November, 194() trance knobs and 19 exit buttons to The knob is hollow and surrounds a the operator may cancel the initiated control 6 single switches, 6 crossovers, separately-supported round disk of condition as described above, or may 2 tunnel protection derails and 19 Lucite, which fits in the face of the wait for the route desired to be avail­ signals. The basic principles of the knob. A white glass arrow in the face able and again press the exit button. NX system of circuits for the control of the knob points in the direction in ·The non-availability of a route is in- . of interlockings were explained in an which the corresponding signal con­ dicated to the operator by following article on page 220 of Raihvay Signal­ trols, and maintains this position. A the desired route across the panel ing for April, 1939, and will, there­ small round white marker, on the and noting whether the red lock light fore, not be given here. outer rim of the knob, indicates the is lighted under any of the route in­ The panel of the control machine is position of the knob, this marker nor­ dicators which must be operated in · 18 in. high and 60 in. long. For the mally being in line with the track and order to secure the desired route. As area within home signal limits and at the base of the arrow in the face the train travels over the route, the the approach sections on the main of the knob. signals go to Stop and remain at Stop lines, each track is represented on the An exit button is mounted in the until the towerman again sets up the diagram by white lines 3/16 in. wide, line representing the track at each route (stick signal) . This is known which stand out in contrast with the point where a train leaves the section as "automatic route restoration." dull black finish of the panel. Small of track over which a signal governs. When lining up a route including lamps mounted in the lines represent­ Each exit button is 9/16 in. in several intermediate signals, the push ing the track are normally extin­ diameter, and normally stands out operation of the entrance knob and guished, but are lighted to show white from the panel 5/16 in. A white the exit button at the end of the when each corresponding track circuit arrow on the face of each exit button complete route causes the switches to is occupied by a train, thus outlining points in the direction a train would operate and all of the several inter­ the route being used. be going when leaving the end of a mediate signals, as well as the one at The switches and crossovers are route controlled by the respective the entrance, to clear. This control represented by small, movable sections button. These exit buttons are oper­ feature is known as end-to-end con­ I of the track which are called route ated by pushing, and do not turn; trol, and eliminates the necessity of indicators. The movable sections are they return to normal position by operating entrance knobs alld exit operated by magnets mounted behind spring action as soon as the towerman buttons for each of the intermediate the control panel, and are actuated to removes his finger. sections. positions which outline the route as When a "closing-in" move is to be soon as the towennan pushes the exit To Line Up a Route made, as, for example, to move a button. An indication as to whether locomotive back onto a train that is each switch is locked is given by a In normal operation, when a route standing within the interlocking small lamp with a red lens mounted is to be lined up, the towerman pushes limits, a "call-on" signal aspect, con­ behind the track lines adjacent to each the entrance knob corresponding with sisting of red over yellow, is used on route indicator. Each such lamp is the signal for the track on which the a two-arm signal; or a single yellow lighted to show red when electric train is to enter the plant. This action may be displayed on a dwarf signal. locking, including the equivalent of causes a red light to flash behind the In order to prevent the operator from mechanical locking, has taken effect arrow in the face of the knob, as an inadvertently allowing such a move, at the corresponding switch, and the indication that the lining up of a he is required to use a distinctive type switch is, therefore, not free to move.: route has been initiated. of manipulation by which he rotates Thus these lamps are known as "lock The next action is to push the exit the entrance knob so that the white lights." bu~ton corresponding to the end of dot or marker on the knob turns the route, following which the route downward through 90 degrees. He Entrance Knobs and Exit Buttons indicators immediately line up to cor­ then presses the exit button as before. respond with the route desired. The A flashing red indication is dis­ In the line representing the track, red lock lights under the route in­ played in the entrance knob until the at the location corresponding to each dicators are lighted at the same time route is lined up. When the signal interlocking signal, there is an en­ and indicate, in conjunction with the clears, the indication changes to a trance knob. As a means of effecting continuous white line, the route which flashing green. In this case the signal different controls, each knob can be has been called for. After the various will not go back to stop when the train pushed, can be turned, or can be switch machines have responded to accepts it. The flashing green serves pulled, and in each instance a different the route called for and the signal to remind the operator that he must set of contacts is operated. The knob clears, the flashing light in the en­ rotate the entrance knob back to nor­ is so constructed that it cannot be trance knob changes to a steady burn­ mal as soon as the train has passed pressed while in a turned position ; ing green or red indication. The the signal. therefore, only one type of control can green indication shows that the signal be initiated. When pushed, the knob has cleared. The red indication is used Special Control of Derails returns to the normal position by with signals which govern beyond in­ spring action, as soon as the tower­ terlocking limits to show that a route The two derails, 7 and 9, on the man removes his finger. When the has been lined up, but that the signal two main tracks are set normally to knob is turned to initiate'a control, it has not cleared because of track oc­ derail cars so they cannot drift down must be turned back to normal in cupancy. When the train ahead moves into the tunnels. When establishing order to cancel the initiation. When out of the block, the signal clears and a route including one of these derails, a knob is pushed to initiate a control, the indication changes from red to the derail is controlled to dear the it may be pulled to cancel that initia­ green. track the same as a switch is con­ tion. If the towerman initiates by push­ trolled in the NX system. After a Each of these knobs is % in. in ing or turning the entrance knob and train uses a route and passes beyond diameter, and stands out 1 in. from the the route desired is not available, the the home signal limits, the switches face of the panel. To facilitate iden­ pushing of the exit button has no remain as they were ttntil another tification, the number of the signal is effect, and the lamp in the entrance route is established. This sort of etched in white, adjacent to each knob. knob continues to flash. In this case operation is not correct . for these November, 1940 R AILWAY S IGNALING o35 -derails because they should be re­ normal or the reverse position, no 100 ft. long was i~"lstalled in the ap­ turned to the. derailing position in route can be set up by NX operation, proach to each stgnal governing a . order to provtde the protection for which calls for the corresponding move out of a yard track. Occupancy which they were installed. For this switch to change its position. A route of each of these sections are indicated reason, the controls are so arranged can be set up, however, by NX opera­ on the diagram by a small white illum­ that when the rear of a train clears tion over the switch in the position inated spot in the track line. the track circuit including a derail, . in which it is held by the test key. The crossover and the 10 single that derail automatically returns to the An innovation in the construction switches are each controlled by a two­ derailing position without any action of this control machine is the use of position lever, these levers being ar­ on the part of the operator. Lucite rod to conduct the proper color ranged in two diagonal rows, one row of illumination to the face of the above and one below the track dia­ Traffic-Direction Through Tunnels machine for switch and entrance but­ gram so that each lever is adjacent to ton indications. Rods of this material that portion of the diagram which The two knobs at the left, on the may be bent as required to reach the represents the corresponding switch. lines representing the tracks through desired position and still the rods will Switch 21 leads to a yard track which the tunnels, are for the control of traffic-direction locking for the con­ trol of signals · to direct train move­ ments by signal indication in either direction on each track between the Windsor interlocking and the 15th St. interlocking in Detroit. Normally the traffic-direction locking is set up for right-hand running. If no train is within the traffic locking section or approaching it, the direction of traffic may · be reversed on either track by cooperative action on the part of the two operators at either end of the tunnels. When necessary for track forces to work on one of the tracks in the tunnels; trains can be run in either direction on the other track by using the traffic-locking system.

Test Keys for Control of Switches

Arranged in rows in the upper sec­ tiqn of this panel are small levers of the key switch type, which are used for test operation of the correspond­ ing track switches. Associated with The lever type interlocking machine for controlling the switches each test key is a corresponding and signals at the west end of the Electric Yard light, which is lighted white whenever the respective switch is either in tran­ conduct light from one end to the is use9, primarily for storing cars, sit or is out of correspondence with other. Color of the light displayed and, therefore, the installation of a the switch position called for by the can be changed by extinguishing one power switch machine was not jus­ route control set up by the NX sys- lamp and lighting another of a dif­ tified. This switch is operated by a -tem or by the test keys. During ferent color. hand-throw stand but a lever No. 21 normal operation of the plant by the is provided and must be operated to NX control system, the test keys are New Control Machine at Tower 3 line up the signal selections for a kept in the normal center position at move over this switch when it is re­ right angles to the face of the panel. The 14 signals, 10 single switches versed by hand throw. A telephone is When the test key is moved to its and 1 crossover at the west end of the provided at this switch so that train­ downward position, the corresponding Electric Yard are controlled by a men can inform the operator when s:witch will operate to its normal posi­ miniature-lever interlocking machine they want to use this switch. tion, and when the test key is moved on the operator's desk in Tower 3, Switch 1 is normally lined for to its upward position, the switch will which is located about 2,800 ft. to the through moves on the straight track operate to its reverse position. This east of this track layout. The face of the eastward freight track. The method of individual control of of the panel is 18 in. high and 26 in. crossover between the two freight switches was provided for use when wide. The main track sections are main tracks is normally open. The a maintainer is testing or adjusting represented by white lines ~ in. wide switches leading from the two ladder a switch. in the panel. Each section has a tracks to the various yard tracks are The movement of a test key is in­ translucent round spot which is illum­ normally lined for through moves on effective to operate its corresponding inated when the corresponding track the ladder tracks. With this setup, no switch when a route including that· circuit is occupied. Cars are left yard track switch has to be moved to switch is established by the entrance­ standing for extended periods on the line up for a Canadian Pacific pass en­ exit control system. Therefore, be­ yard tracks, and, therefore, track­ ger train when moving over the north fore using the test key, any existing occupancy indications would be of no ladder track. route controls including the switch use. In order~that the operator may The switch levers stand normally in must be cancelled. Conversely, if the know when a train is ready to pull the vertical position, thus controlling test key has been left in either the out of a yard track, a track circuit the corresponding switches to their 636 RAILWAY SIGNA LING November, 1940 normal position. \Yhen a switch is All westward moves from any one of track. If lever 12 is thrown to the to be operated to permit a train move­ yard tracks 2, 4, 6, 8 or 10, to the right, signal 12R clears for a move­ ment into 01- out of a yard track, the eastward freight track or over switch ment along the ladder track or into corresponding lever is thrown 90 deg. No. 1 reversed on the connection to any one of the yard tracks for which to the right. A white lamp b~low each the main track, represented one cate­ the switch has been reversed. Thus switch lever is illuminated when the gory in which only one of five signals, as long as crossover 11 is normal: lever is thrown and continues to stay 2LA. 2LB. 2LC, 2LD or 2LE, could movements to or from each group of lighted until the switch moves to the be cleared at any one time. Eastward yard tracks can be handled independ. corresponding position and is locked, moves into any one of the yard tracks, ently in either direction by the two then the indication lamp is extin­ 2, 4, 6, 8 or 10, from the eastward signal levers. When crossover 11 is guished. This indication is known as freight track or the lead from the reversed; no signal for a route con­ the out-of-correspondence lamp, and. main line represented another cate­ trolled by the left position of signal in case the switch does not follow the gory in which only one of the signals, lever 1, nor any signal for a route lever contl-ol. the operator thus has 2RA or 2RB, could be cleared. Ob­ controlled by the right position of sig­ this information at once. viously neither 2RA or 2RB could be nal lever 12, can be set up. There· A red lamp in the face of each cleared when any one of the five op­ fore, when crossover 11 is reversed switch lever is illuminated when the posing signals, "'2LA to 2LE inclu­ signal lever 1, when thrown to th~ switch is electrically locked and not sive, was cleared. Based on these right, controls signal 2RA or 2RB. free to be thrown. Since pre-condi­ facts, one lever, No. 2, at the lower depending on whether switch 1 is nor­ tioning is nrohibited. this light con­ left of the panel, controls all of the mal or reversed, and signal lever 12, stitutes a "Hands Off" light. If the seven signals, 2RA, 2RB and 2LA, when thrown to the left, controls any operator should throw the switch lever 2LB, 2LC. 2LD and 2LE. When the one of the six signals 12A to 12F when this light is lighted, the switch lever is thrown to the left one of the inclusive, depending on whether all will not operate even though electric 2L signals clears, depending on the switches are normal or any one locking is subsequently released. Both whether all yard switches are normal reversed. When a signal lever is the lock light and the out-of-corre­ or which of the switches, 9, 7, 5 or 3, thrown and •' the corresponding signal spondence light will remain lighted. has been reversed. When the lever is clears, a wh1te lamp in the face of the The operator is obliged to return the thrown to the right, signal 2RA or signal lever is lighted. Since the yard switch lever to the last position, and. 2RB clears, depending on whether signals are not track circuit controlled, if the lock light is extinguished, he switch 1 is normal or reverse. the lamp remains lighted until the is then free to throw the switch. When signal lever 12, at the upper operator puts the signal to stop by left of the panel, is thrown to the left. placing the signal lever normal. Only Two Signal Levers Required with all yard switches normal, signal Having cleared a signal. all of the 12LA clears. If any of the yard switches involved are automatically An analysis of this layout showed switches, 15, 17, 19 or 21, has been locked. After the train accepts and that only a limited number of routes reversed, the corresponding 12L sig­ passes the signal,. all the switches in­ could possibly be used simultaneously. nal clears for .a movement from that volved are automatically locked by the detector locking. Therefore, even though the operator might inadver­ tently throw a switch lever, no action of the switch would take place. If the operator clears the signal for a train on any approach circuit. and then "takes the signal away" by moving the lever, no switch in the route can be moved and no opposing or con­ flicting signal can be cleared for a period of 15 sec., which allows time for the train to stop short of the sig­ nal or to enter the home signal limits The Type-A relays and thereby maintain the locking on are enclosed in a the switches and lock out opposing sealed c a s e with and conflicting signals. transparent cover Circuits for the Yard Plant

Direct-wire circuits are used for controls and indications between track layout at the west end of the yard and the control machine in Tower 3. All vital or safety circuits are local in the field with the relays located in a welded-steel factory-wired hous­ ing at the field location. For the non­ vital circuits between the housing and Tower 3, a common wire is used for practically all of the circuits. One wire and common from each switch lever controls a polar relay in the field which in turn controls the operation . of the switch. This same wire, through the use of a series relay in Tower 3, November, 1940 RAILWAY SIGNALING o37 is used to indicate when the switch is locked. A second wire and common is used to indicate switch position at Towe~ 3 by m ~ans of a polar relay repeatmg a sw1tch-repeater relay in the field. This same wire is also broken through the detector track relay so that a track-occupancy indi­ cation may be obtained, in conjunc­ tion with a locked indication, over the same control wire. Thus only two wires and a common are required to control and indicate the position of each switch, and, at the same time, to Detachable Type­ indicate whether the switch is locked B relays and three and whether its detector track is tower-type switch controllers in the occupied. instrument r a c k One wire and common is used in conjunction with each of the signal levers to control a polar relay in the housing which in turn clears a "left" signal when operated by one polarity and a "right" signal when operated by the opposite polarity. The signal will, of course, not dear until all switches in the route are in their proper posi­ tion and are electrically locked in that position. The signal indications and the rest of the track indications are brought in over individual conductors in asso­ ciation with a separate a-c. common. These indications are obtained direct from an a-c. source without the use of any relays in Tower 3. In this con­ nection, it should be noted that the short track circuit on the yard tracks in tower-type controller controls the and new brush holders and brushes are not provided with relays and are operation of each switch directly. . were provided. The coils were re­ normally on open circujt. The pres­ Space was available in the case of taped. The main cam gear wheel of ence of an axle on the track circuit each machine to house a po~nt:detec­ each machine, as well as the bridle completes a circuit to light the indi­ tor for the control of a polar .switch­ rods, were replaced with new ones. cation light through a suitable step-up repeater relay. The point detector is The 110-volt battery, for operation transformer. The aerial cables be­ the over-and-locked type, and was in­ of the switch machines, consists of !ween the interlocking and Tower 3 stalled together with connecting rods, 56 cells of 120-a.h. Exide EMGS-7 mclude 1 No. 6 wire, which is com­ etc. The pole-changers were rebuilt storage. battery. A set of six cells mon for the diagram lights, and 48 or replaced with new ones. New lock feeds the signal control circuits. A set No. 14 wires, of which 2 are spares. blocks were installed. New covers for of 16 cells, with a center connection, is the locking compartments, of the type used to feed the small relays of the Switch Machines Overhauled to permit the locking to be visible NX network. These various sets of were provided. The motor shafts and batteries are on floating charge The switch machines, which were bottom bearings were all replaced. through dry-plate rectifiers. in service at these interlockings, are The commutators were turned down, (Continued on page 641) the Model 4, equipped for operation o? 110-volts d-e., using individual d1r~ct-lever control and dynamic indi­ catwn. In order to use these switch machines in the new interlocking con­ trol systems, several changes and ad­ di~ions were necessary, and the ma­ chines were completely overhauled. In the new system of control, a plug-

The switch machines were completely rebuilt, point­ detectors w e r e installed and various o t h e r parts were replaced or repaired November, 1940 RAILWAY SIGNALING 641 permit operation of the lever. After New Interlocking teries and accessory equipment re­ operation of the emergency release quired in the plant controlled from the electric lever lock on the switch at Windsor, Ont. Tower 3. lever is released, and the lever can be (Continued from page 637) On account of the fact that 600-volt moved to the opposite position and d-e. traction energy is used on the the red lever indication lamp is Underground parkway type cable rails, the track circuits are of the a-c. lighted, but t~e switch d~es not oper­ was used to install an entirely new type. As a part of the improvements, ate. At th1s time, a spectallamp unit wiring distribution system between the old galvanometer type a-c. track adjacent to the main signal is the signals, switches and the instru­ lighted, which is an indication tD the ment room or house. Between the motorman of an approaching train west end of the Electric Yard and that the plant is not in normal oper­ Tower 3, aerial cables are used in­ ation. He stops his train short of the cluding two 19-conductor, one 12- signal. With his car controller in the conductor cable No. 12 and a single "off'' P?Sition, he can remove a key conductor No. 6. These cables are from hts controller and place it in a about 2,200 ft. long and are supported key-hole controller on a box so located on poles spaced 100 ft. apart, using on the wayside that he can easily reach Copperweld stranded messenger and it when opening the door of his com­ Raco cable strap hangers. The mes­ partment. When the key is turned in senger is grounded at each end and this controller, circuits are completed at the middle point. to cause the switch or switches to operate to the position corresponding Instrument and Battery Housings with the positions of the switch levers. as is indicated by the red lever in­ A room 18 ft. by 8 ft. 9 in., in the dication lamp being extinguished. southeast corner of the Windsor sta­ The leverman then returns the emer­ tion building was used to house the gency release to normal position. relays and other accessory equipment Then the !everman reverses the signal required at the control station of the lever and operates the push button \Vindsor plant. Another room ll;Yi corresponding to the signal ; after ft. by 12 ft., which was partitioned 1 off which the signal displays the "call-on • in one corner of the baggage room, Battery charging apparatus aspect and the train-stop trip at the is used to house the storage batteries. Near the location of old Tower 2, an relays were discarded, and new Type­ signal clears. In the meantime, the N vane a-c. track relays were in­ motorman removes his key from the 8-ft. by 10-ft. sheetmetal house was stalled. These track relays for the wayside device and returns it to its provided to include the relays, bat- Windsor plant are all in outside relay normal position in his car controller. cases and are repeated by Type-B so that he is ready to accept the signal i'n and proceed. d-e. plug-in relays the relay room at the station, and those in the yard interlocking are all in the sheetmetal Emergency Operation of Switches ·house. Although great care has been taken Quick-Detachable Relays to prevent the failure of the air sup­ ply to this plant, nevertheless arrange­ The control relays of the interlo_ck­ ments have been provided such that ing systems are all of the G.R.S. if the pressure does fail, the switches Type-B quick-detachable plug-in type can still be operated to keep trains and are mounted in panels supported moving. in angle-iron frames which rest in In case of an air pressure failure, rubber shock absorbers on the floor. the raising of the hasp on an A-10 The small relays for the control of the electro-pneumatic switch machine, NX networks and the various indica­ affords access to a receptacle in which tions on -the control panel of the a crank can be inserted to crank the Windsor plant are the G.R.S. Type­ switch from one position to another. A, quick-detachable type, and are Once the hasp has been raised, the mounted in sealed cabinets with trans­ openings to the normal air supply are parent covers. cut "off" and locked "off" by a latch­ These new iriterlockings were ing arrangement which cannot be re­ planned and installed by signal forces set until released by means of a key in of the Michigan Central, under the a Yale lock device, and this key is direction of R. E. Green, assistant retained in the possession of the main­ signal engineer. L. Rupert, circuit tainer on duty at the plant. engineer, was assigned to this project · This new interlocking was installed to develop the plans and inspect the under the direction of Ed Blake construction and installation. F. M. Superintendent of Way and Struc­ Brown; signal supervisor, had general tures of the Hudson & Manhattan. supervision of the construction. The The interlocking equipment was fur­ new control machines, signals, relays, nished by the Union Switch & Signal rectifiers and replacement parts for Company. which prepared the detail the switch machines were furnished plans and performed the construction by the General Com­ work. box near signal 12 LA pany.