Leaving NEP on the inner rail just as the sidings split from the main, there is a small brick structure on the left. It has been there for years. It reminds of an old sentry guard box (albeit made from brick) Anyone know what it was for? I assume it was built after LT took over the GER line.
I've always assumed that buildings of that style were associated with traction current supplies. There are several such buildings dotted around the network. Referring to the yellow peril for Newbury Park I find that there was a traction switch house located more or less where the brick building you describe is located. I suspect that this must be what the building is. The traction switch house was provided in connection with the long gone car sidings and allowed them to be fed from either the inner rail or from a direct feed from Newbury Park substation. The switch house also contained the circuit breaker for the sidings, which was effective regardless of which supply was used. Presumably it was the presence of the circuit breaker which necessitated a full blown brick structure, rather than the more usual changeover switches in yellow boxes.