This is a 3D model of a Oahu Sugar company water car used on the island of oahu hawaii. The model is deigned to use Bachmann ez mate mk2 couplers and HO scale wheel sets. A truck tuner may be necessary to help the cars free roll better depending on the wheelset used. 

Coupler pins are included with the kit. They go into the round slots on the underside of the model. Install your couplers and slide the pins into place. They are designed to be a tight fit so they don't fall out.