User Interface Controls Operation of Märklin Model Railway

The Igor graph represents the layout for my Märklin model railway. The graph is drawn by a command-line interpreter, which permits any arbitrary layout to be generated by selecting from a set of pre-defined objects.

Moreover, many of these objects are "live" - they can be used to actually control the real objects, which they represent. For example, signals can be raised or lowered simply by clicking on their icon; similarly, points (I think in US nomenclature they are switches) can be set to straight ahead or left or right etc. The action happens via Igor's VDT2 XOP communicating with an Arduino mega, with lots of relays.

It is a user interface as well as a graph - and a novel programming technique.

The models, which I started collecting in my childhood, were manufactured between 1957 and 1963 and are purely electrical devices, not digital or even electronic. They are still being made but I have eschewed "upgrading" to the more modern digital versions in favour of the superior Igor solution.

Submitted by: Frank van Kann <frank.van.kann@uwa.edu.au>