Circuitron
Emergency Flasher

.120" Red
Walthers Part # 800-3002, p. 773 Walthers 2012 HO Scale Reference
A scale, $19.95, currently in stock at Walthers

 
A low-cost circuit that alternately flashes two LEDs at a constant rate. Animate emergency vehicles, signs, barricades, towers, etc. Simple to install. Powered by a 9V battery, or by using PS-3.