Check the listing for details. Track Voltage Tester for Model Railways Trains (N, TT, HO Scale). Condition: New. Listed at 8.44 USD. Can be used with analog or DCC systems. The track voltage tester is a handy little tool perfect for fault-finding or ensuring electrical connection when building a new layout, whether you’re running DC or DCC through your rails. Simply place the tool on top of the rails, light pressure may be required, and the LED will light up either green or red for DC voltage, or orange (green/red) for DCC voltage. If the LED doesn’t light up, there is no power in the track! As pictured the tester indicates DC polarity either side of the LED. When the LED lights up red, negative is on the left, positive on the right. Vice versa when the LED lights up green. The tester is not polarity sensitive for DCC voltages. Compatible with HO and N scale trackTested to work across the range of 0-24VContact pad gauge tolerance (what gauge of track can the tool measure)8 – 20mm gaugeOnly allows for N, TT and HO gauge track (9, 12, & 16.5mm)Overall dimensions: 24 x 14 x 12mm (LxWxH)