Grand Scales General Code of Operating Rules – First Edition – January 1, 2007
8.0 Block System Rules
Signal Color Instructions 8.1 Signal aspects and indications are shown in the special instructions. Signal aspects are identified by the position of semaphore arms, color of lights, flashing of lights, position of lights, or any combination. Signals may display colored light aspects or semaphore arms and color lights.
Signals On The Right 8.2 When viewed from the train, block and interlocking signals are generally to the right of the track. However, they may be located to the left or above the track. To display indications for two tracks, two bracketed signals may be located on a single supporting mast. The signal to the right governs the track to the right and the signal to the left governs the track to the left.
Block Signals 8.3 Block signals govern the use of blocks (sections of main track). Interlocking signals govern the use of interlocking routes. Where a track is signaled beyond the interlocking limits of the direction of movement, the interlocking signal is also a block signal.
Missing Light 8.4 Except as shown in block and interlocking signal aspects in the special instructions, if a light is absent or a white light is displayed where a color or lunar light should be, regard a block or interlocking signal as displaying the most restrictive indication it can give. However, when the semaphore arm position is plainly seen, that aspect will govern.
Over run Signal 8.5 When movement is being made beyond a block signal requiring a train to be prepared to stop at the next signal, the stop must be made before any part of a train passes the block signal requiring the train to stop.
If a train overruns any block signal that requires it to stop, the crew must:
warn other trains at once by radio,
stop the train immediately,
report it to the train dispatcher or proper authority.
Except to avoid an accident, after a controlled signal has been
cleared for a closely approaching train, the control operator must not change the signal before the approaching train’s engineer has assured the control operator that he can comply with the signal change. Do not establish or authorize a conflicting route until communicating with the approaching train’s crew and ensuring that the train has stopped clear of the conflicting route.