A couple of guys I know are into the big "G" scale model railroads, so I built these controllers for them
The first one is a standard traffic light controller that will syncronize the north/south and east/west lights for an intersection, the other one is for the wigwag lights at a railway crossing.
The controllers can be used for any scale of railway, just use different LEDs.

N-scale 3mm LED
HO-scale 5mm LED
G-scale 10mm LED

The controllers have bridge rectifiers on the power inputs, so they will accept anything from 6-30v ac/dc to power them.
This is a new design using pic microcontrollers, so if you want to control full sized traffic lights, just hook the outputs up to relays with 5v coils (100ma max load per output). They are programmed for a 10 second red/green and 3 second amber cycle, but can be programmed for any length you want

Here are some pictures of them set up as counter displays

 

Traffic Lights

Wig-Wag Lights