Thomas Trackmaster Coal Tender Coupling

This is to replace a broken coupling on Thomas Trackmaster trains that have the battery for the engine in a permanently-attached coal tender. If you need the couplings that go between the engine and the cars (non-permanent attachment), check these out:

https://www.thingiverse.com/thing:2104759

http://www.thingiverse.com/thing:1620364

I designed this with notches for a zip-tie to hold the wire in place that runs between the engine an the coal tender. This allows you to just cut the broken coupling off so that you don't have to fully remove and desolder the wire to put this replacement coupling in. Put the coupling in, then zip tie the wire to the coupling.