Connecting a track detection point to an s88 module

The technique of obtaining train location feedback from the train layout is well known and one typically uses a Märklin s88 module or one of the many modules that perform the same or similar service, such as the Viessmann 5217 modules.

Understanding how to connect the length of isolated track to the port on the module is one aspect of the job. Another is the technique of how to actually get the signal from the track all the way around to where the s88 modules are located. This page documents my technique for doing this.

Philosophy of digital train control

Background

Controlling model trains with a computer has been around since 1986 when Märklin introduced their digital system. Since then there have been numerous improvements and a wealth of new digital items and products. Some things have, however, remained the same. All digital systems consist of decoders (usually in locomotives) and they are all controlled by computers, even if the computer does not look like a computer. The Märklin digital controllers, the Intellibox, ECoS and Viessmann controllers are all computers. Some of these controllers also allow computer input from general purpose computers such as PCs and Macintosh machines and allow greater flexibility and power in controlling a train layout digitally.

Laying K-track

I have just a little bit of track left to wire up so I decided I had better document how I do it before I have nothing left to photograph...

Martinez type contact

On my old layout, I needed to add some sensors in a hidden area that was very unaccessible.

This is how I planned on adding an s88 contact point as needed in hidden areas of the layout. The advantage was that I could simply glue the assembly down next to the track without having to lift track, cut rails and relay the track.

A big disadvantage was that track cleaning devices were likely to destroy the switch or get hung up on them.

Antonio Martinez has a much simpler technique using aluminium foil.  I am abandoning my experiment and have started my first Martinez type contact. I stuck a length of packaging tape on one side of some foil (thus insulating one side), then cut it out with a tail of bare foil that I twisted and fastened into a Märklin socket for easy connection to the s88 lead. Here it is, insulated side up.

I can them simply pin it down over one side of the rail so that it cannot touch the center studs and covers one running rail. If it wears out I can easily make another to replace it.

Update: These tin foil switches worked without any problems for over 9 years. Even then, they did not fail, they were taken out of service as I dismantled the layout.