Factorio Forums

In the changelog for version 0.17.38 it said:

/u/FactorioTeam wrote:This also allowed us to to let train recalculate path spontaneously even in chain signal sequence, as it shouldn't break anything now.

By 'spontaneously' I assume they mean according to the rerouting rules described here: https://wiki.factorio.com/Railway/Train_path_finding

Specifically:

• The train starts braking for a signal (chain or regular) it cant reserve. The train is forced to recalculate its path.

This could only occur at the end of a 'blockchain' because all of the chain-signalled blocks in front of the train are already reserved.

I thought I could leverage this new behavior to create a lane switcher that allows faster trains to overtake slower trains when there's no oncoming traffic. However, it seems that rerouting inside a blockchain doesn't actually work beyond disabling train stops, as this simple test shows:

https://streamable.com/6b2bk

Question is: am I missing something and can someone show me an example of rerouting within blockchain without the effect of train stops becoming disabled?

If you put a chain signal or normal signal directly in front of the junction then it should work. If you want to build a lane switcher like that then you have to use more signals anyways because the train that wants to overtake the slow train should enter the second track as fast as possible.