Just a note to anyone else who's working on the Sydney rail system - I'm starting to add electrification tags. Just finished Blacktown to Richmond. We use a 1500V DC overhead contact wire. If you want to help, the tags that need to be added to all electrified rail lines in Sydney are [electrified=contact_line], [frequency=0], and [voltage=1500] (Note that frequency=0 is necessary to denote DC).

@aharvey - I'm considering inventing a tag for railway signals but that's still waaaaay down my mental to-do list.

Another method would be to work off a video (with relevant permission of course). Like this -

http://www.youtube.com/watch?v=_v4fNeIhMns