It's really cool that they can use the train tracks to bring stuff into and out of the station. It seems obvious in retrospect, but that had never occurred to me before.
https://www.nydailynews.com/new-york/mta-refuse-rigs-collect...
Similarly, all materials for that project enter and exit from the other end of the project tunnel in Queens. New York City at ground level has no indication that the work is ongoing 140 feet below their… well, feet. Very neat!
I think they move them to sidings in central London very late in the evening, so that after the last passenger train has departed (00:30-01:00) the equipment/materials can be where they're needed in just a few minutes.
[1] https://en.wikipedia.org/wiki/London_Underground_engineering...
[2] A web search for "London Underground engineering train".
[3] http://cartometro.com/cartes/metro-tram-london/ (detailed map, showing sidings etc)
https://untappedcities.com/2016/02/12/the-mtas-special-armor...
A lot of time, materials and tools are simply loaded through the station manually and since you are not allowed to store anything flammable below ground, some of it needs to be taken back out at the end of the shift.
They are not keen to lose station time but sometimes I think they could afford to lose an hour either end when they are doing engineering work in a station. At least in this instance, they needed to close the station which saves so much time.