How bout mounting a chainsaw without the bar on that thing?? You would have to gear it down some unless you really wanna fly, but its pretty well already set up for what you are looking to do....just a little noisy.
How much $$ would a guy be lookin at for 1 section of track like you have with rails, ties and tie plates?? How long are the rail sections, 10-12' or so?
I prefer the human powered notion, also.