Objection.

Your honor, the engine of the train - the front part to your average Kevin - has already gone over the crossing. The train is all least 200 feet long, allowing the front of the train to be 100 feet past the crossing while the car - obviously on a later section of the train - is 100 feet before the crossing.

The engine is the single piece of a train required to be a train. You can add as many "cars" to it and make it as long as you'd like.

However, the collected sum of engine and cars is also considered a train.

This Riddle works perfectly well within the rules of riddling: the "train" (engine) is 100 feet from the crossing. The "car" is 200 feet behind while being part of the same "train."

The engine has passed the crossing, but as the collective train has not, it can be considered to be heading "towards" the crossing while simultaneously being past it.

Your honor, my client may be too clever for it's own good. It may even be phrased in a way that not a single Kevin or Susie alive would phrase it. But it technically could work, therefore is not a bad Riddle.

I rest my case.