This isn’t quite row 3, column 4 on the bridge bingo card but why don’t they do away with the bridge entirely? Just dig out the hills on both sides of the bridge, have the train cross at the level of the road, and put in gates to block traffic when a train is coming through.
There may still be people who try to sneak around or through, but the city could post the remains of the first truck to try to do that (as it would lose the fight against the train) before the intersection as a very vivid warning for future drivers not to try it.
