The polarity (or train direction) of the rails is shown on the tester. -Small enough to check point frogs.
Train-Tech TT1 Multigauge Track Tester DC/ DCC OO, HO, N Gauge
Train-Tech TT1 Multigauge Track Tester DC/ DCC OO, HO, N Gauge Boxed
Train-Tech TT1 - LED Multi Gauge Track Tester DCC/DC For N/H0/00 Gauges - RM48P
Train-Tech TT1 - LED Multi Gauge Track Tester DCC/DC For N/H0/00 Gauges ++ RM48P
Train Tech TT1 Track Tester+ for N/OO9/HO/OO Gauges
Gaugemaster GM52 Multi Scale Track Tester
