Factorio Forums

I'm trying to get my first multi-train track working, but either I can't figure out signals or my design is busted. My base is supposed to have two unloading stations with a loop on the end; there are two corresponding iron stations on the other end of the track (each iron station has its their own loop). The idea is that the trains shouldn't be able to get stuck, because you can always wait for the other train to go to its station and then drive around it. But I think the loops are interacting badly with signals. Can this type of design work, or must all my rails be one-way?

Base top station: Base bottom station:

The way the loop is signaled, it would wait at the chain signal until the other signal turns green which will not happen because the train itself blocks it. Add some more signals, or remove them both if you only ever want one train in the station / loop area.

But that's not what causes the 'no path' message. The first picture has a split track where both tracks have a signal on one side, the same side, so trains can only go south there. This could be the problem.

The wiki has a good guide for resolving no path/general errors. Here is a good guide for general signalling.

That said the main problem seems to be that the whole top part is one way track heading south. The west track should be made two way. You should also probably add a chain signal between the top station and the merge so that the other train can pass. I'd also remove the signals on the loop they'll only cause trouble.

I think that should make it work, hopefully

R = rail signal
C = chain rail signal
arrows indicate direction of travel.
yellow "=" indicates those two signals are directly opposite each other to allow for two-way travel.

The yellow rail signal in the bottom right would be optional and only if there is space on the loop before and after to fit an extra train, this would allow two trains to fit on the loop if you want. I hope this helps, this is how I would signal it.

Very thorough comments from others on the signals.

One thing to be mindful of: an advantage of RORO style trains/stations (as opposed to top-and-tail trains) is that one train can pull into a station at the same time as another one is exiting. Your current setup doesn't allow for this.

The disadvantage of RORO stations is that the loop can make them bigger. The disadvantage of terminus stations is that a train must leave the station entirely before the next train can enter. It seems that your current setup has elements of both.

An alternative would be to have the exit track merge back onto the mainline separately from the entrance track.

Thanks everyone for the help, especially Kelderek for the annotated images! I managed to get it working.