Marklin, Inc
K Track

Curved Circuit Track 16-3/4" 424.6mm 15 Degrees
Walthers Part # 441-2239
HO scale, $16.98, currently in stock at Walthers

 
Enables automatic control of turnouts and signals by a train in operation. Activated by a pickup shoe on a locomotive or car, they can activate different circuit switching functions independently in both directions of travel. Length 1/2 = 15 degrees. Radius 16-3/4" 424.6mm.