Dear SMC1957 -

BTrain is a free and easy to configure app for running a layout in the way that you describe, BUT only for Mac computers. The learning curve for Rocrail & JMRI is longer. No experience with other apps.

Link here.

Osoraku

Buff... Sorry. My ignorance is such that I have no idea what to do when I get to your link for the app. Compile? No idea how to do it nad my MBP 2023 M2 has no Xcode app in it.

Thanks anyway.
Santiago

Thank you again.

Just for clarification, because I see that many read my post, but few answer. I am asking about CONTACT TRACKS needed for a single track shadow station with capacity for 4 trains in total.

Santiago

Hi Santiago
Here is a Märklin HO digital fan using Rocrail since 2013 and today operating with a CS3 a Link S88 and many m88 AC modules

One possible solution to your problem is using Rocrail one or many STAGING Blocks
Here is to the Rocrail info Rocrail Staging Blocks

What is a staging block?
- suppose you have a very long strech of line (2,5 M in my case) and have a block that could host multiple trains of variyng lengths behind each other with the best possible use of the length.
- this is called a STAGING BLOCK (Bloc de transfert en Français or Aufstellblock in German)
- the staging block is divided into a number of segments (number is selected by YOU). The more segments you have , the best use of the available length
- Rocrail must know the length of each train and the length of each segment (your choice, all identical or varying lengths.
- that way Rocrail may reserve for each train, the number of segments it will occupy
- a long train may occupy multiple segements
- the staging block is ALWAYS one way (cannot use it in di-directional mode

Here is how it looks

Don't be afraid by the large number of parallel blocks here.

Sorry I cannot show a video of my staging block as it is in a shadow station. In my case 7 segments (up to 7 very short trains behind each other
It is working very well.

If you are interested, I may help
Cheers
Jean

Santiago, Its me again
In my case I had a strech of 2,5 M and I divided it into 7 segments of the same size (for simplicity).

Before telling more I need to say that the Rocrail staging block drives the train as V_min (basically the lowest substainable speed (no stalling)

At the end of each segment you need an occupancy detector so that ANY train driving at its OWN V_min will slow down and stop exactly at the end of the determined segment.
The rest of each segment is EITHER without detection (my case) or with another occupancy detection (you must add one entry per segment).

For precision of detection lengths and position, I cut one of the rails of my wide radius C Track at the exact location

The detection length I used for each segment was approx 10 cm within the approx. 350 mm segment length.

The staging block must also have an ENTRY detector (a new train is entering the staging block)
This is how I ended up at 8 sensors total for 7 segments

Rocrail staging block ask you for a SECURITY DISTANCE. This is a minimal distance Rocrail ADDS after its calculations. In my case 30 mm

I may have had issues with the staging block but NEVER did I have a collision caused by miscaculation

Even though the detection may not be perfect, Rocrail manages to find its way. I don't encourage the rails and wheels to be dirty, BUT the system is pretty safe.

Because a normal block hosts only ONE train, its name is displayed which is not possible with a staging block. So I wrote a little program to display which segment contains what train

Here is an extract of my Rocrail plan in the staging block area


You may see that Segment 1 and 2 are free, segements 3 to 6 are occupied by a long train BR_50_98 and segment 7 (closest to exit is occupied by the BR_95_004 loco
XML program is available for you if you are interested

Cheers

Jean