Welcome to this forum, and back to the hobby!

1. A block is a certain length of a track between turnouts, that could fit your (longest) trains (see principle in the drawing below). If you have a long line between your turnouts, you could define several blocks on the line. iTrain will NOT automatically see the presence of trains within your blocks.

2. You need at least one sensor per block. Two sensors - one track piece at each end of the block - are better as then they could notify iTrain to initiate trains to BRAKE and STOP, in each direction. Adding a third sensor, for the track between the initial two sensors, is even better in order to provide OCCUPATED notification to iTrain.

For most blocks, I use two sensors only. A good software package knows where your trains are anyway. You need some hardware between the tracks and iTrain:

Most users here rely on the ”s88 feedback bus”. Then sensors need to be connected via m83 modules (Märklin 60832) to which you can connect 16 sensors. I use an alternative from Littfinski, the RM-88-N-O. There are a few more brands providing s88 feedback modules. With C track, you simply cut and isolate one rail on the sensor track(s), and let the the isolated rail to the s88 module, for reading when the track is occupied.

I notice that you are using the Roco z21. Or the Z21 Black? However, myself I’m a Märklin central station user and I guess you cannot apply the s88 bus directly. Then you would need e.g. a HSI-88 module from Littfinski, to connect between the feedback module and the computer.

There are probably other feedback buses than s88 that could be connected to the z21/Z21, but I’m not really familiar to the Roco control unit. My main concern is that you need to find a feedback module using ”earth connection” for reporting feedback. Two-rail feedback systems most often report on ”power consumption”, which you don’t want as it would only report OCCUPATED where the pickup-shoe is.

3. You need decoders to control turnouts and signals from iTrain. It’s easy to spend money in the digital world! The type of decoders you need depends on the type of turnout motors you go for - The Märklin way? The servo way? Same with signals, there are those that are digital from the box, there are those that need to be controlled by decoders providing short pulses, and there are those that simply have LED’s that you need to control with a switch type of decoder.

4. No. Running digital from a software package like iTrain, most users have signals for ”the show” only. I.e. the signals don’t control anything, especially not track power OFF/ON.

You will find more detailed help searching this forum or google the net. And of course, by asking directly in this forum.

Edited by user 05 December 2023 07:03:18(UTC)  | Reason: Typo

You need both to derive an isolated rail for your feedback sensor! ”Cutting C tracks” means cutting the two connections between the two rails on each sensor track. The red insulators are needed to separate the sensor rail from other tracks. Below is an excellent clip describing how to make feedback tracks/sensors.

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