Circuitron
FLW White Strobe

Bright 1.4mm Lamp, 1.5V
Walthers Part # 800-1031, p. 773 Walthers 2012 HO Scale Reference
HO scale, $18.95, not currently in stock at Walthers, Expected: Unknown

 
Bright white flash from small incandescent lamp (included). Battery or track power adapter powered. Same size as FL-1.