Having more than one vehicle working a single route usually means that after a while, the vehicles tend to bunch up together. I had previously thought it may be minute differences in delays introduced through, for instance, waiting for a free path for trains, differences in cargo loading time or random breakdowns.
But even playing a game without breakdowns, and looking at the vehicle with the most stable route, ships in this case, the vehicles still bunch up together after a while with amazing reproducibility - behold!
Trains and buses both exhibit this too, though it's harder to illustrate this problem with them. I know that timetables should prevent this, but building good timetable is hugely time consuming and quite difficult to do on a large scale.
Is there some sort of game mechanics that's causing this, and what can I do to prevent this from happening without the need for either manual intervention or timetabling?