Circuitron
TP-3 Track Power Adapter

Walthers Part # 800-2003, p. 773 Walthers 2012 HO Scale Reference
A scale, $18.95, not currently in stock at Walthers, Expected: 29-Feb-2012

 
Ideal for constant lighting source in unpowered rolling stock. No ballast lamps or motors required. Will power Mars flasher in models driven by low current can motors. Works with all forms of track power. Max current output is 1/2 amp.