Factorio Forums

Trains can pass through the gap between wagons/locomotive without stopping or damaging/destroying the other train or itself.
See the screenshots below or easily reproduce it in the game.

Thanks for the report,

I can confirm that the collision boxes leave a big enough gap for a perpendicular wagon

I don't know what all ramifications would come from changing the train collision bounding box but they have been this way since trains have been a thing so they can stay that way for a while longer.

Maybe in 0.14 we'll change them but not for now.

First off, train signals don't allow this trick. Second, this trick requires a decent amount of precision each time it is used. Thusly, the potential for abuse is low.