nun als ich 2004 in London war hatte ich mir das Greenwich Kraftwerk genauer angeschaut und sah durch ein Gittertor Schienen - aber weit und breit kein Anschluss. Die Sonne hatte gescheint und dachte erst (das Tor war ja Abgeschlossen!) das ist ein Trugbild aus Sonne und Schatten.
doch als ich mich getraut habe dort im RMweb nachzufragen habe ich folgende und auch interesannte Antwort bekommen!
It wouldn't be unusual for power stations to have rails set into the ground to assist the infrequent shifting of heavy equipment where overhead cranes alone could not provide for the movement, or there may have been some other railway-like purpose, perhaps for the removal of waste, using suitable internal wagons or trolleys. Certainly Greenwich had no rail connections to the outside world.
I can provide some information on an internal light railway system at Greenwich, however.
Greenwich was the principal source of power for the LCC tramways. It was supplied with coal by ship as it was built on the Thames riverside. Coal was taken from the ships by three cranes on a high-level jetty and loaded into purpose-built hopper wagons, designed for direct bottom discharge into the bunkers within the building.
The wagons ran on standard-gauge track direct from jetty level to the bunkers, and were hauled by two 'locomotives' built on standard 21E 4-wheel tram trucks with standard tram control equipment and end platforms. Each loco had a box body and roof extending over the platforms at each end. Locomotives took power from an outside third rail.
My sources for this are:
London County Council Tramways Volume 1 - South London by E. R. Oakley LCC Electric Tramways by Robert J. Harley.
The latter book includes a picture of the high-level jetty with locomotives, hopper wagons and track in view.