Little Car

I have been puzzling over a piece of code since yesterday, and finally saw what the issue was. The original is from a book by a group of (Russian) coders, and it moves a little train along with speed defined in terms of a cubic Bézier. In my mania for code by the book, I couldn't get my little car to move along like the original. Remember, in CSS one would specify margin-left, while in JavaScript, marginLeft. What makes the car move smoothly is using the moniker 'left' in both cases.!!??

The html file:

 The style.css file:

 Bezier values one can try: