After many hours and a lot of money hacking up old and new trains to power the first round of models, I made for Maker Faire I thought someone out there must have had this problem before. I know this might be outside of what most modelers would encounter since most diesel engines are roughly the same length or width.
The internet does allow you to find models of just about anything that existed out there in the real world and if not, someone has modeled it in CAD. After a lot of internet searching and research, I did find some solutions. The solutions range from what I did hacking up an existing locomotive to finding module parts from other companies to get something to work. Tomix seems to have the largest selection of these module parts. They do fit the needs of many modelers just fine, but they are hard to get a hold of here in the states. I don’t know about you but my Japanese is not what it use to be and flipping between their site and what you can find on ebay does leave you wondering if what you are reading is what you are about to buy.
Even if you get what you want you now must figure out how to get it to attach to the body or chassis you have. There are compromises made along the way as well. It might not be the most robust setup, truck spacing may not be ideal, couplers need to be aligned or cut off and in the end, you have a very expensive locomotive that might not be ideal.
As I have been still searching for a solution to this problem, I just decided to build my own. The design constraints I imposed are that it would have to use off the shelf parts or materials. It should not be locked into a proprietary component (proprietary motors)instead it should be able to use parts from existing manufactures (think spur gears, DCC boards, lights, couplers etc). Also something that could be scaled up easily for larger gauge trains.
After many iterations I think I came up with a viable solution. The Uni-Rail powered chassis system uses 3D printed parts, brass rods, nylon gears and off the shelf DC motor to give the modeler a platform on which they can modify to fit the build they are working on. I am still working on the details of this system but in the end I hope it will help other to build a powered car, locomotive or subway car they way they see it in real life or in their imagination.