ryan125hst
Established Member
In areas that are signalled using Absolute Block, part of the duty of the signaller is to look for the tail lamp at the rear of the train. The presence of the tail lamp indicates that the train is complete and therefore the 'Train Out Of Section' bell code can be sent to the adjacent signal box. This is required due to there usually being no track circuits between signal boxes in absolute block signalled areas, and at one time, many freight trains were unfitted, meaning that they didn't have an automatic brake throughout the train.
However, some signal boxes control more than just a couple of running lines. It's possible for pair of slow lines to supplement the fast lines for example, and there may be additional lines such as goods lines to add to the mix as well. With multiple lines to watch, how does the signaller make sure they are able to check the tail lamp on every passing train? Surely it is possible that if two or more trains are passing at such a time that the rear of multiple trains is passing the signal box at the same time then it will be difficult to check for the presence of the lamp on every train? Could there be instances where a train closer to the box obscures the view of trains on lines further away from the box? And what about boxes where a line passes behind the box as well as in front?
What happens if a signaller misses the back of the train and therefore can't confirm it has left the section complete?
However, some signal boxes control more than just a couple of running lines. It's possible for pair of slow lines to supplement the fast lines for example, and there may be additional lines such as goods lines to add to the mix as well. With multiple lines to watch, how does the signaller make sure they are able to check the tail lamp on every passing train? Surely it is possible that if two or more trains are passing at such a time that the rear of multiple trains is passing the signal box at the same time then it will be difficult to check for the presence of the lamp on every train? Could there be instances where a train closer to the box obscures the view of trains on lines further away from the box? And what about boxes where a line passes behind the box as well as in front?
What happens if a signaller misses the back of the train and therefore can't confirm it has left the section complete?