Elephant & Castle stabling sidings

Is there a train crew depot at the elephant?

Yes there is a train crew depot at Elephant & Castle.

Also, you can't change the advertising posters if a train is parked in the platform.

There's a whole heap of work that can't be done with trains stabled in platforms! Of course when we were resignalling the Bakerloo in the late 1980s they had to find somewhere else to put them every night because we were working in the platforms and the sidings.
I can recall when I was renewing the tunnel telephones and local T/T cabling some time afterward when the trains were stabled in the platforms. I needed access to the southbound platform track area one night and made a local arrangement with the controller the night before to park the train, that was to be stabled there, elsewhere. He made arrangements to have it stabled in the sidings which were otherwise empty. So on the night I was working in the platform running cable but I didn't know where the train had been stabled, assuming the sidings were normally always occupied, as a chap approached to have a word. "Would you believe it, I'm supposed to be working in the sidings and made arrangements with the controller last week to leave them empty but there's a train in the Southbound"! He was not amused when I told him that I had, had the train shifted from the platform but I couldn't help laughing over it. I have no doubt that similar disappointments occur to this day even though SABRE was invented last decade to formalise and coordinate arrangements for all planned works in engineering hours.

IMHO there should never be any clash situations in engineering hours except in extreme emergency and much of the potential of SABRE to make life simpler for all engineering installation and maintenance staff and contractors was lost by not having suitably qualified and experienced works planners within the track access organisation who fully understood the relationships between the engineering requirements and tasks of different disciplines and how they did or did not impact upon one another.
I know the operating department owns the railway but even so it should not be running trains in engineering hours which which impact upon works planned months in advance just because of an incident earlier in the day. No doubt operating would argue that say a signal failure in the morning rush hour would have a knock effect to services accumulating throughout the day leaving trains at the wrong end of the line, running out of turn etc causing otherwise unaffected services to be curtailed for other reasons such as inevitable late train pickup, crews stranded in the wrong place or due to go off duty before completing a rounder etc.
Having to move trains outside traffic hours in order to rebalance, as far as is possible, depot fleet levels in order to maintain mandatory rolling stock inspections and provide the next day's services are not really valid reasons for destroying the first hour or two of engineering hours unless the situation is the result of an incident occuring late in the timetable.
The loss of engineering maintenance and inspection work due to the reduction of engineering hours often has a much greater knock on effect lasting days or weeks due to having to plan such work three or more months in advance. Such can thus have an ongoing effect upon the reliability of future passenger services, an unseen and perhaps unappreciated result of fighting to 'regain service' following an incident.
Of course there is a financial cost too, not just the actual and potential loss of revenue but the cost of paying hundreds of people to do nothing due to lost time events over the course of year and the additional unplanned costs of paying some people to work additional hours at premium rates to complete essential tasks etc.

I doubt that service controllers give any thought to the difference that compliance with a simple request not to leave a train in a particular place on a particular shift makes apart from the effect it has upon the following day's services.

"Having to move trains outside traffic hours in order to ....provide the next day's services are not really valid reasons for destroying the first hour or two of engineering hours unless the situation is the result of an incident occuring late in the timetable. "

Wow. The job of the underground is to provide a service to its customers. If engineering has to be postponed or delayed then it's unfortunate (except safety critical stuff that absolutely can't be postponed 24 hours - unlikely). I can understand that it may be very frustrating but you must bear in mind the big picture. The reason the underground exists is to "provide the next day's service".

The only time we get to cancel a engineers train or a special train i.e stock moves or test train running is if someone will impact the service the next day. Regarding these S stock test runs sometimes they are at short notice (on the night) and we get no prior warning until at least 22:00 on the night so planning works is very hard especially on Tuesday's and Thursday's when the majority of them operate.