I'm not sure what compelled me to make this, but here it is! The first human-powered vehicle for BeamNG, rife for your painstakingly manual rail adventures, and ready for the inevitable BeamNG machinima remake of Blazing Saddles.
The handcar is designed to work on railed maps such as Sultan Peak and Tennessee, USA. To operate, you'll need to push the handcar off using either the forward (Y) or rearward (H) thruster. After that, you'll use either the left and right arrow keys on keyboard, or the X-axis of the left stick on gamepad to push the walking beam back and forth. It's a bit tricky to learn, but is an interesting kind of immersive once you get the hang of it.
I have to commend the makers of Substance Painter, as the 30-day free trial version was responsible for generating the granular details of this project. I have to say that I recommend, especially if you're a quick learner.
Bear in mind that it's a far cry from fast on level track. And before you ask, yes, you'll need rails to make this function almost at all.