The polarity (or train direction) of the rails is shown on the tester.
GAUGEMASTER Multi Scale Hornby Track Tester GM52
Train Tech Multi gauge Track Tester N/TT/HO/OO Gauge TT1
Track Tester for power and faults - N/OO/HO - Train Tech TT1 -
Gaugemaster GM52 Multi Scale Track Tester
Gaugemaster GM52 - LED Multi Gauge Track Tester DCC/DC N, H0/00 Gauge - DSA
Train-Tech TT1 - LED Multi Gauge Track Tester DCC/DC For N/H0/00 Gauges ++ DSAPo
