Thx Zephyr1934, unfortunately I made a mistake. The guard site is smaller instead of broader. The chassis is 6 studs, the front at the driver-side will be 7 studs, the other side with the round parts are up to 8 studs. The drawing is made in Bricklink studio, and I use their parts numbers. I wil gather the cheapest bricks I can get.
For the track I have the idea to print them from ABS. Not in the standard Lego form, but only in the standard gauge. I will start with R72 or R88.