Hi,
I saw a passing (stop and start) 1995 stock passing earlier today which wasn't in service, and was wondering how often trains running on the network are not in service (which the stock is in regular service)?
I've seen the S stock when it was on test but that would have made sense since it was a few years ago when I saw it happen.
Loads of reasons. Some possibilities are:
Stock move between depots (can run in service if this won't cause disruption and the rolling stock is otherwise fit for service)
Defective train moving between depots
Test run of previously defective stock
Test run for testing purposes
Train gone defective during trip
Training train covering moves and therefore too disruptive to run in service
Train going back to depot after incident (e.g. One under)
Train being driven by manager (not allowed to carry passengers except to next station)
Soiled car (normally vomit awaiting cleaning)
Driver tired or unwell (sometimes staff will accompany but as a precaution train may run empty)
Booked empty on timetable for whatever reason (normally to avoid having to tip out at an inconvenient location)
Doubtless other reasons too...
It's common to get stock moves between depots during the inter-peak period and also during the evening, at both times a priority for controllers is getting the 'stock balance' right for the evening peak or next day - especially at minor stabling points where there may not be a spare train or space to handle a surplus.
As an aside, I know someone who managed to get an extra empty train to run one evening to move a locker from one station to another. Nowadays there probably wouldn't be spare staff sitting around to do that...
