 Although a cable haulage system had initially been considered , Ramsgate Olympia decided early in the line 's planning to electrify the line . A third rail system was rejected due to concerns for the safety of the large numbers of children expected to use the line , and the locomotives had trolley poles drawing power from a single 400 @-@ volt DC overhead line running the length of the tunnel . The wire ran along the wall of the old tunnel , on brackets in the roof of the new tunnel , and was supported by poles at the open @-@ air stations . The electricity was supplied by an electrical substation built by English Electric , inside the tunnel near the lower end . 
