The Board of Transport
Commissioners for Canada
Commission des Transports
du Canada

Order no. G.O. 806

Friday, the 18th of
February, A.D. 1955

In the matter of regulations respecting the installation and changes to automatic block signal systems, traffic control systems, and station protection signals:

45417

Hugh Wardrope
Assistant Chief Commissioner

F. M. MacPherson
Commissioner

H. B. Chase
Commissioner

It is ordered

  1. That the following regulations respecting the installation and changes to automatic block signal systems, traffic control systems, and station protection signals be, and they are hereby prescribed for the observance of every railway company within the legislative authority of the Parliament of Canada.
  2. That the said regulations apply to new installations only and do not apply to existing installations made prior to the date of this Order.
  3. That General Order No. 736, dated the 4th day of January, 1950, be, and it is hereby rescinded.

Regulations in Respect to Installation and Changes to Automatic Block Signal Systems, Traffic Control Systems, and Station Protection Signals

  1. Without the approval of the Board no company shall install or make any major change in automatic block signal systems, traffic control systems, or station protection signals.
  2. With the application for such approval the company shall send to the Secretary of the Board three sets of a combined plan and profile, showing tracks, gradients and alignments for the territory on which the signals are to be installed, and with the location for proposed signals shown thereon.
  3. Definitions and symbols approved by the Signal Section of the Association of American Railroads shall apply for the purpose of these requirements.
  4. The apparatus shall, so far as possible, be so installed and circuits so arranged that failure of any part of the system affecting the safety of train operation will cause all signals affected to give the most restrictive indications which conditions require.
  5. Signals shall be located preferably to the right of and next to the track they govern.
  6. Signal aspects shall be shown by the position of semaphore blades, position of lights, colour of lights, flashing of lights or any combination thereof. They may be qualified by marker plate, number plate, letter plate, marker light, shape and colour of semaphore blade, or any combination thereof subject to the following conditions:
    1. Night aspects of roadway signals, except qualifying appurtenances, shall be shown by lights, day aspects by lights or semaphore arms. A single white light shall not be used.
    2. Reflector lenses or buttons or other devices which depend for visibility upon reflected light from an external source shall not be used in night ,aspects, except qualifying appurtenances.
    3. The aspects of cab signals shall be shown by lights or by illuminated letters.
    4. Each aspect displayed by a signal shall be identified by a name and shall indicate action to be taken. Only one name and indication shall apply to those aspects indicating the same action to be taken. The same aspect shall not be used with any other name and indication.
  7. The fundamental indications of signal aspects shall conform to the following:
    1. A red light or a series of horizontal lights or a semaphore blade in the horizontal position shall be used to indicate stop.
    2. A yellow light or a series of lights or a semaphore blade in the upper quadrant at an angle of approximately 45° to the horizontal, shall be used to indicate that speed is to be reduced and a stop may be required.
    3. A green light, a series of vertical lights or a semaphore blade in the vertical position shall be used to indicate proceed at authorized speed.
  8. Each signal shall be located with respect to the next signal or signals in advance which govern train movements in the same direction so that the indication of a signal displaying a restrictive aspect can be complied with by means of a brake application, other than an emergency application, initiated at such signal, either by stopping at the signal where a stop is required, or by a reduction in speed to the rate prescribed by the next signal in advance where reduced speed is required.
  9. If an arm of a semaphore signal assumes a false restrictive position or if a lamp in a light signal fails, the signal shall not display a less restrictive aspect than intended.
  10. On track signalled for movements in both directions a train shall cause one or more opposing signals immediately ahead of it to display an aspect requiring a stop. On such track signals shall be so arranged and controlled that if opposing trains can simultaneously pass signals displaying proceed aspects, and the next signal in advance of each such signal then displays an aspect requiring a stop, the distance between the opposing signals requiring a stop shall be not less than the aggregate of the stopping distances for train movements in each direction. Where such opposing signals are spaced stopping distances apart for train movements in one direction only, signals arranged to display restrictive aspects shall be provided in approach to at least one of the signals. Where such opposing signals are spaced less than stopping distance apart for train movements in one direction, signals arranged to display restrictive aspects shall be provided in approach to both such signals.
  11. Signals shall be automatically controlled by continuous track circuits extending through the entire block, excepting as otherwise permitted.
  12. Signal control circuits shall be so installed that each signal governing train movements into a block will display its most restrictive aspect when any of the following conditions obtain within the block:
    1. When it is occupied by a train, locomotive or car;
    2. When points of a switch are not closed in proper position;
    3. When an independently operated fouling point derail equipped with switch circuit controller is not in derailing position;
    4. When a track relay is in de-energized position; or
    5. When signal control circuit is de-energized.
  13. Track relay shall be in de-energized position wherever any of the following conditions exist, and the track circuit of an automatic train stop, train-control or cab-signal system shall be de-energized in the rear of the point where any of the following conditions exist:
    1. When a rail is broken or a rail or switch frog is removed, except when a rail is broken or renewed in the shunt fouling circuit of a turnout or crossover, provided, however, that shunt fouling circuit may not be used in a turnout through which permissible train speed is greater than forty-five miles per hour. It shall not be a violation of this requirement if a track circuit is energized when a break occurs within the limits of the joint bars or rail-joint bond or as a result of leakage current or foreign current in the rear of a joint where a break occurs or a rail is removed; protecting signals shall be arranged to display their most restrictive indication and immediate steps taken to correct such condition when found;
    2. When a train, locomotive or car occupies any part of a track circuit, including fouling section of turnout, except turnouts of a handoperated main track crossover. It shall not be a violation of this requirement where the presence of sand, rust, dirt, grease or other foreign matter on the rail prevents effective shunting;
    3. Where switch shunting circuit is used;
      1. Switch point is not closed in normal position;
      2. Switch is not locked where facing point lock with circuit controllers is used; or
      3. An independently operated fouling-point derail equipped with switch circuit controller is not in derailing position.
  14. Signal control and electric locking circuits shall not be selected through the contacts of instruments designed primarily for indicating or annunciating purposes in which an indicating element attached to the armature is arranged so that it can in itself cause improper operation of armature.
  15. The battery or power supply for each signal control relay circuit, where an open-wire circuit or a common return circuit is used, shall be at the end of the circuit farthest from the relay.
  16. A signal governing movements over hand-operated switch shall display its most restrictive aspect when the normally closed point of a facing point switch is open one-quarter inch or more or when the normally closed point of a trailing point switch is open three-eighths inch or more, except that where a separate aspect is displayed for movements over the facing point switch in the normal and in the reverse position the signal shall display its most restrictive aspect when the switch points are open one-fourth inch or more from the normal or the reverse position.
  17. The control circuits of signals governing movements over a main track facing point spring switch shall be selected through the contacts of a switch circuit controller or through the contacts of relay repeating the position of such circuit controller which, when normally closed switch point is open one-fourth inch or more, will cause such signals to display their most restrictive aspects except that where a separate aspect is displayed for such movements over the switch in the reverse position the signal shall display its most restrictive aspect when the switch points are open one-fourth inch or more from the normal or the reverse position.
  18. Indication of signal governing movement from siding to main track over a spring switch or governing movements against current of traffic from reverse main of main tracks to single track over a spring switch shall be Stop when, on signalled track, a train is approaching within 1,500 feet in rear of approach signal located stopping distance from the main track signal governing trailing movements over the switch, except that indication may be caused to be less restrictive if approach or time locking is used.
  19. Electric locks on new installations and new electric locks applied to existing installations shall be of the forced drop type, or the equivalent.
  20. Where non-coded or non-reversible track circuits are in use and where energy to one track circuit is supplied through the front contacts of an adjoining track relay, the energy circuit to such track circuit shall be open and the track circuit shunted when such relay is in de-energized position.
  21. Fouling section of turnout shall extend to clearance point.
  22. The length of any track circuit, except trap-circuit or special circuit not used for control of signal facilities, shall be greater than the maximum inner wheel base of any locomotive or car.
  23. Where a dead section exceeds thiry-five feet special circuit shall be installed. Where shortest outer wheel base of a locomotive operating over such dead section is less than thirty-five feet the maximum length of the dead section shall not exceed the length of the outer wheel base of such locomotive unless special circuit is used.
  24. Signal wires carried on pole lines shall be securely tied in on insulators.
  25. Insulated wires shall be protected from mechanical injury. The insulation shall not be punctured for test purposes. Splice in underground wire shall have insulation resistance at least equal to the wire spliced.
  26. Wires shall not interfere with operating parts of mechanisms.
  27. Each wire shall be tagged, or otherwise marked, so it can be identified at each terminal board where practicable. Nomenclature shall correspond to that of the circuit plan. Tags or other marks of identification in instrument cases and apparatus housings shall be made of insulating material and shall not interfere with moving parts of apparatus.
  28. Lightning arresters shall be properly connected. Where grounded the resistance to ground preferably should not exceed 25 ohms.
  29. Track shunt wires and fouling wires, except shunt wires to switch circuit controller through which signal control circuits are controlled and track circuits are shunted, shall consist of at least two conductors and each conductor shall be of sufficient conductivity and maintained in such condition that the track relay will be in de-energized position when the circuit is shunted.
  30. At hand-operated crossover between main tracks protection shall be provided by one of the following:
    1. An arrangement of one or more track circuits and switch circuit controllers;
    2. Facing point locks on both switches of the crossover, with both locks operated by a single lever; or
    3. Electric locking of the switches of the crossover.
  31. 31. Signals governing movements over either switch shall display their most restrictive aspect when any of the following conditions exist:
    1. Where protection is provided by one or more track circuits and switch circuit controllers, and either switch is open or the crossover is occupied by a train, locomotive or car in such a manner as to foul the main track. It shall not be a violation of this requirement where the presence of sand, rust, dirt, grease or other foreign matter on the rail prevents effective shunting;
    2. Where facing point locks with a single lever are provided and either switch is unlocked; or
    3. Where the switches are electrically locked, before the electric locking releases.
  32. The electric lock on hand-operated switch shall be controlled so that it cannot be unlocked until control circuits of signals protecting such switch have been opened. Approach or time locking shall be provided.
  33. Signals controlled by devices used to provide protection against unusual contingencies such as landslides, dragging equipment, burned bridge or trestles, and washouts, shall be located so that stopping distance will be provided between the signal and the point where it is necessary to stop a train.
  34. Measures shall be taken to prevent recurrence of an aspect displayed by a light signal, different from the aspect intended, caused by light from an external source being reflected by the optical system of the signal.
  35. Outdoor signal and instrument cases shall be locked.
  36. The normal functioning of any device shall not be interfered with in testing or otherwise without first taking measures to insure safety of train operation which depends on the normal operation of such device.
  37. Switch circuit controllers, facing-point locks and switch-and-lock movements and their connections shall be securely fastened in place, and contacts provided with an opening of not less than one-sixteenth inch when open.
  38. Circuit controller operated by switch-and-lock movement shall be provided so that normally open contacts will remain closed and normally closed contacts will remain open until the switch is locked.
  39. Track circuit shall be provided so that track relay will be in deenergized position if, when track circuit is dry, a shunt of 0.06 ohms resistance is connected across the track rails of the circuit, including fouling sections of turnouts.
  40. Insulated rail joints shall be installed so as to prevent sufficient track circuit current from flowing between the rails separated by the insulation to cause a failure of any track circuit involved.

Additional Regulations Applicable to Traffic Control Systems

  1. The control circuit for signals governing movements at higher than restricted speed over switches, movable-point frogs and derails shall be selected through circuit controllers operated directly by the point of such switch, frog, or derail, or by switch-locking mechanism or through relay controlled by such circuit controller, for each switch, movable-point frog and derail in the route governed by such signals. Circuits shall be so arranged so that such signals can display an aspect to proceed only when each switch, movable-point frog and derail in the route is in proper position.
  2. Indication locking shall be provided for power-operated interlocking signals, power-operated switches, movable-point frogs and derails, and for all approach signals, except light signals, all aspects of which are controlled by track circuits, or by line circuits which do not include a common return circuit.
  3. A power-operated approach signal shall be provided on the main track to govern the approach with the current of traffic to all interlocking signals, except when the authorized speed of trains approaching the interlocking signal is slow speed or less, in which case an inoperative approach signal displaying an aspect indicating approach next signal prepared to stop may be used. Exception may be made where the interlocking signal is the first signal encountered when leaving yard or station and authorized speed approaching such signal is not more than slow speed.
  4. Signals governing movements at higher than restricted speed shall be controlled by continuous track circuits.
  5. At controlled point, signals shall be controlled by control operator, and at manually-operated interlocking, manually in co-operation with control operator.
  6. Signals at a controlled point shall be so interconnected that aspects to proceed cannot be displayed simultaneously for conflicting movements.
  7. Signals at adjacent controlled points shall be so interconnected that aspects to proceed cannot be displayed simultaneously for conflicting movements.
  8. On track signalled for movement in both directions occupancy of the track between opposing signals at adjacent controlled points shall prevent changing the direction of traffic from that which obtained at the time the track became occupied.
  9. Occupancy of main track shall be automatically indicated at the control station.
  10. Approach or time locking shall be provided for all controlled signals and for all electric locks on hand operated switches.
  11. Route locking shall be provided where switches are power operated.
  12. It shall be indicated on the control machine when power-operated switch has completed its movement and is locked.
  13. Each hand-operated switch in main track where train movements are made at speeds exceeding 20 miles per hour shall be electrically locked in normal position. Electric locks may be unlocked either automatically or by the control operator, but only after control circuits of signals governing movements over the switch in each direction have been opened. Relief from this requirement may be granted upon adequate showing by the railway.
  14. Plunger of facing point locks shall have at least eight inch stroke. When lever is in reverse position plunger shall pass through lock rod one-half inch or more.
  15. Locking dog of switch-and-lock movement shall extend through lock rod one-half inch or more in either normal or reverse position.
  16. Pole changer on electric switch operating mechanism shall be provided so that movement of switch mechanism follows movement of controlling lever.
  17. Point detectors shall be provided so that when switch mechanism is locked in normal or reverse position contacts cannot be opened by manually pplying force at the closed switch point. Point detector circuit controllers shall be provided so that the contacts will not assume the position corresponding to switch point closure if the switch point is prevented by an obstruction from closing to within one-fourth inch of its proper position.

Hugh Wardrope
Assistant Chief Commissioner,
The Board of Transport Commissioners for Canada.