Algodoo

This is a track that I made for the beginning of a tank, and it has a track tensioner. It also has a drive mechanism so you can put an engine in it and power it. I tried putting one of my engines in it but they were all to big, and they don't scale down well, so maybe you might have better luck. If you put anything heavy on it you will probably have to raise the density of the track and wheels to 10-15, and probably increase the spring strength.