Interesting, thanks! Will that mean the electrical areas are divided into smaller sections, reducing the impact of an isolation?
They are replacing TIS's, (Track Isolating Switches) which are the little grey boxes you may have noticed between the substation and the track. These boxes contain a simple knife switch operated by an insulated pole with a hook. Essentially it has been deemed deemed that they were not a safe way to isolate the track and the act of placing a bar down to short circuit the conductor rail to the running rail was also not ideal for the operator either.
For every DC track circuit breaker there was a TIS associated with it. Now, TIS is gone and a TFS (Track Feeder Switch) is in its place
So the electrical sections remain the same size, they just (potentially) make an isolation quicker, safer and easier.
The ambition is to enable the TFS's to be controllable remotely by Sandhills Electrical Control which could in theory reduce the impact of an emergency isolation (or emergency switch-off as we need to call them now) as the conductor rail can then be isolated and shorted at the click of a button.
Note - they don't take away the role of Track feeder circuit breakers, as a DC circuit breaker dealing with high current is quite specialised, and a TFS can only be operated with the track dead.
Here's some pictures inside