Technical rail maps - digital info available?

["Sam Lander" <netwrk@ozemail.com.au>]

Apologies if this is a FAQ...
Is there a source for technical Sydney rail maps? The kind of info I am
after is:
   Signal, trainstop and sensor locations
   Switches and throwpoints
   Stations and platforms - used and disused
   Gradients and curvatures
   Speed limits
   Comms links - radio, fibre, mechanical and electrical
   Road and rail tunnels and bridges.
And, going one better, is there a digital source for this info?

Sam
sam_lander@yahoo.com.au