The Nix Trainz Power Bridge products are the solution for DCC to avoid operation and sound interruption while running your trains. Once the power on the track is switched on, the supercapacitors of the Power Bridge start charging. When the locomotive experiences power loss because of dirt on the track or on a turnout or crossing frog, the Power Bridge kicks in and assures the loco will continue for a few seconds. Power Bridge I and II can be wired as a three-wire power pack or two-wire stay alive. The units have three wires to be compatible with power pack compatible decoders. The white wire is a data cable, through which the Power Bridge is switched off when compatible decoders are being programed. Power Bridge can also be configured to be a two-wire stay alive by combining the white with the red wire to U+ on the decoder output. Both Power Bridge I and II have one super capacitor. Power Bridge III is a two-wire stay alive that can also be used in place of a three-wire power pack. It does not need to be disconnected during downloading or programing. The device has a very small footprint. It uses two small super capacitors in series, both of which can be installed away from the circuit board, allowing you to fit this device in small HO or even some N Scale locomotives. Check out the entire line of Nix Trainz DCC products and accessories.