I tried a similar method than the first one suggested by isidoro but my trains got stuck at signals (I must still learn how to place signals correctly)… maybe that was the problem, but is it correct not to place signals just as isidoro did ? Shouldn’t signals be placed on all four tracks entering the junction ?
I think that the correct way of doing the roundabout is the one I posted. I assume that all the tracks are one-way. We have four directions: NE, SE, SW, NW, each with an entrance track and a leaving track. I also assume that trains drive on the right. If you consider this, there are four one-way signals just in the four entrance tracks.
That way you avoid a train just stopped at a signal and blocking the roundabout. If trains are long, if stopped at a signal at the roundabout, they could block an exit and another train could come in and prepare a deadlock, I guess.
The problem with both solutions is that if they are kept small, the speed limit is very low and the trains have to reduce their speed a lot when approaching the roundabout or the crossing.
