With the layout is set around the early 1960s in mechanical territory most of the cupboards would still be of wood as it assumes an L&Y box with renewals by the LMS. In such areas the standard LMS cupboards were used right up to closure, the coming of Multiple Aspect Signalling or renewals during the 1970s. I remember putting in LMS style cupboards on MAS stageworks in 1969.
Because most places like this were still powered by batteries there wasn't much option for boosting the voltage so lead lengths on track circuits would necessarily have been kept short. Track circuits were powered by a pair of AD608 Air Depolarised primary cells in parallel. These were about 4" square and 8" high IIRC. Track Relays were all shelf type and the repeat relay circuits to the box were powered by batteries of 3 or 4 DS1 dry cells per circuit. Arm and light repeating for signals out of view of the box would also be powered by DS1 cells.
At the box as there were only a small number of relays these would be in a cupboard under the box, as would the batteries required for repeat relays, lever locks, Blocks and phones.
As Sheffield had rather thick air at that time I would expect that there wouldn't be any telegraph wires except for possibly to a cabin over the tracks from the cable run. The cables would have been in wooden trunking or buried in pipes. I have details of some trunking if you want it.
Eric