Here is my implementation
Cross made of 6cm ss pipe. Cross member situated at 3 ft with one end threaded flange with neoprene rubber seal. Vertical member 7ft. Top will have 1w solar panel rigged for 12 v o/p. electronics self built mp3 player (no ogg dac-codecs yet afair) in loop mode with stereo fm tx hooked to Nokia limh battery hooked to car charger hooked to solar panel.
Person walks up to cross Bar places both hands on bar reads any braille that may be there. He is now correctly oriented. Tunes fm reciever to the prefixed frequency (which is the same for all beacons) and listens to the endless looped message. Message will start by providing rail info - u are at prabhadevi C - followed by instructions about getting to nearby locations and bus stops.
A central server having details of all beacons and corresponding surrouding locations can provide fine details and needed interactivity. Both ogg and graphics acn be served.
Busses have the same set up as crossbar but with a directional antenna near the front door. Collision detction seems technically un feasable at the moment.