Week 1 & 2 Jan Flashcards
What is the principle of absolute block?
To prevent more than one train being in a section on the same line at the same time
What is the definition of the absolute block?
The line between the last stop signal (which can be a section signal or a IBHS) controlled from one signal box and the home signal controlled by the next signal box.
Station limits
The line between the home signal and the section signal worked by the same box in the same direction of travel
What is the intermediate block section?
The line between the section signal and the IBHS worked by the same signal box in the same direction of travel
Clearing point
The point beyond the home signal up to which the line must be clear before a train can be accepted as shown in regulation 3.4.1
Clearing point track circuit
The track circuit or circuits beyond the home signal that controls the block indicator
Home signal
The first stop signal controlled by a signal box that controls the exit from the absolute block section
Section signal
The stop signal that controls the entry to absolute block section or IBS
IHBS
The stop signal that controls the exit from a IBS and the entrance to an ABS
What are the clearing point distances?
Semaphore 400m. Colour light aspect 183m
7 Bell codes no attention
2 3-5-5 6 1-1-6 1-2 2-5-5 4-5-5
What criteria must be met before offering train to signal box in advance?
Receive train out of section (2-1) for previous train. Block indicator for the line concerned must be normal
Sending train entering section to advance signal box
When the train passes the signal box or location in the signal box special instructions
If there is an IBHS when may you clear the section signal for the train to enter the IBS before offering the train to the signal box in advance
As long as the track is clear up to and including the overlap track circuit beyond the IBHS
If a train is beyond your signal box before it has been accepted by the signal box in advance and you have an IBHS, when do you send the train entering section?
When the train has been accepted by signal box B and the IBHS has been cleared