Egads, I don't know if I can TOFTT this one, folks. Why is the Moto 9000 a steam train if it's got ion thrusters? (Maybe those are bubbles and not steam?) How do boxcars count as oncoming trains? At least it's got rockets! Interesting game idea though. Make it a space train on the moon (low gravity, fits the tech). Zoom out a bit, make it 5 or 6 tracks wide. Have both slow trains that you're passing and fast trains traveling towards you. Have both engines and cars behind them. When your train jumps you'd have a neat effect of your engine jumping and the cars jumping over just slightly after it like a slinky. Now THAT I'd buy.
Each of the 5 enemy boxcars have different qualities. Red ones are normal. Green ones can shoot back at you. Yellow ones are super-fast. Purple ones have extra armor. Black ones are invincible. You'll find that the gameplay is very fast-paced and frenetic! I'll upload a video to youtube soon so you can see it in motion!