TL;DRThis is a “counter suggestion” to Trains: Chain signals should factor in the length of the train.
What?Introduce signals, that blocks trains with some (measurable) train (!) properties from driving through the block, where the sign is placed.
You can prevent trains crossing such signs.
- trains longer/shorter than x
- trains with/without cargo x
- ... (fuel lower than x? Filter double headed trains? Trains with special equipment?)
Implementation looks relatively simple: I think that could be easy added to the pathfinding. (?) because such signs work just like a broken rail. You cannot place the sign everywhere, for example it makes eventually no sense at crossings. I guess the most effort for this feature goes into the GUI.
No path: if a sign blocks a train from arriving his target it alerts the player. If the signal was changed after the train has been left station (path had been found), and an alternative cannot be found, it ignores the sign.
Nice to have: The sign could also be controlled by circuits. Again: if the sign changes and there is no alternative path, it ignores the sign.
Why?Give the player a way handle trains with very different length. You cannot build good, fast crossings for any type of train. That makes such crossings inefficient. Instead enable the player to route trains to an optimized version for their length.
Other options can add very much gameplay value with a relatively low effort.
- avoid crossings that the train with that length is not build for (the origin of this idea)
- route longer trains around the center of your factory
- make “main lines”
- with control by circuits: route around busy crossings
- route low fuel trains to stops with a refuel
- make waiting lines for one item type only
And many things more.
This is also quite related to the suggestions of adding penalty signs/signals to influence the pathfinder.