As building a drop and pickup station for the secondaries it is always a hard task to build such a station. You must care about flow and speed to get the most effective station, impede by the enviroment like cities, industries and transmitters. What we are talking about are stations with about 20 entries, served by a ML which got 3-4 lines. It require a lot of skills to build a proper joiner after the station and an even better splitter before the station that it can handle a huge amount of trains. This results in a lot of tunnels, brighes, presignal and so on...

The Idea

At some time I have thought about a station layout which can handle every traffic amount by extending the station always the same way. My idea was the station is 90 deg turned by the track the trains come from. The trains so passes the station until they find a free slot and enter it. If the traffic is to much I extend the station with new slots. Then you add the presignals and it works... for slow traffic. As a train in the presignal area will block the whole presignal other trains have to wait at the beginning, even if there are a lot of slots free.

As you see the train which enters the station blocks the other train for joining the last slot. So I thought about some presignal stuff which transport the information "slot is free" from the slots at the end to the presignal at the beginning. I did this with a second line, similar to priorities.

Notice how the free-slot information is "traveled" thought the marked tiles around the train which blocks a segment. With this presignals the station can enter the presignals even if there already a train on it.

How to improve the layout

After the idea the station layout must be improved. As you see only a half of stationslots are used and cannot be used from this side as the signals blocks the entry. But they can be used from the other side.

But how do they exit the station? This is not a real problem, I often use tunnels as followed.

If the trains leave the station they have enought space in the tunnel to wait if the exit isn't free yet. You can see the exit from the upper part goes east, the exit from the lower part goes west. This can be flipped/switched however you need it. You also see the disadvantage of this layout. This station and all tracks and signals with a TL of 5 are 23 tiles width. You need around 18+TL tiles space for the width. But - and thats the advantage - you can extend this layout as long as you need.

You see here again you can choose from where the trains comes and where it go. This can be changed as whatever you want.