If you do a Google Image search for "Gnitro Gnat" your "dragster on rails" issues may be sorted. The story is told on Gnatterbox at http://mrhpub.com/2016-12-dec/online/html5/index.html?page=132&noflash It was ever only a straight-line runner (what would you expect for a dragster??) The anti-tip-up wheels on the rear couldn't handle curves.
Unfortunately both the model and the builder are no longer. The Gnitro Gnat predeceased its builder by several years. The Gnitro Gnat was positioned on top of the builder Jim Favre's computer monitor in the days of big CRT display monitors. Unfortunately Jim accidentally bumped the monitor and "Gnitro" took a fatal fall to the floor whereupon it exploded.
Another tall tale and true from this hobby's legendary past, RIP Jim, your modelling lives on in the internet,
Unanderra in oz