The other guy I ran these cars with had one that had the left rear wheel attached directly to the crankshaft. It was an all white O&R29 see the picture at the bottom of the page.

We were using .012" solid wire on the aluminum cars and nylon string on the Cox air car and we were using a tennis court to run them. The posts would lift out of pockets. It was smooth. The wire broke one day and that put an end to my nice Cox/Cameron car. I was only 12 yrs old and another part to that story is that I was using my bicycle rear wheel to start the aluminum cars. I was holding on to one of the chain stays and turning the pedal with the other hand. Some how my hand slipped on the chain stay and a spoke took off my thumb nail. The temperature was in the low 50's and that sure did ache. I had to ride the bike home with that sore thumb.

you will notice in the videos that a guy has to support the wire until the car gets above 45 mph and then he jumps up on a little platform. The California track is recessed between the actual track and the pylon.
This picture if visible is of the Long Island track