Cecil’s answer to the question “What makes a car so prone to stall in the middle of train tracks?” moved almost immediately into a discussion of why this might be a matter of perception rather than of reality. But I think there is good reason why stalls on RR tracks are more likely than, say, in the middle of a street.
Having owned a few stall-prone cars in the past, I recall that the most common situation in which they would stall was when I 1) had it in gear, 2) was moving very slowly, almost-but-not-quite stopped, and 3) began to gently press on the accelerator to give it just a little more gas.
Now, that pretty much describes the situation I would be in whenever I was about to cross a speed bump, railroad track, or particularly nasty potholes/broken pavement. I slow way down just before my front tires encounter the obstacle, give a bit of gas to ease them over, then repeat for the back tires.
I suspect that this pattern is common among many drivers, and could easily lead to stalls just in front of, or directly over the tracks.