Model Railroading with Digital Command Control

Märklin DIGITAL and HyperCard

Controlling Märklin Z with a Personal Computer

This is the general scheme of controlling the magnetic devices like turnouts, signals etc. of a scale Z (mini-club) train via Märklin's DIGITAL devices and a Personal Computer.

Note that Märklin no longer supports/recommends using its current DIGITAL devices for scale Z. This was not always the case: Around 1987 they included detailed hints how to control Z turnouts, signals, etc. in their book about Digital control, using the same Digital control system as for their H0 scale products with 3-rail AC power. There was even an exhaustive connection scheme for the Z turntable.

Some time later Märklin announced a special version of its Digital control system for 2-rail DC systems, and that it would be available for scale N (from Arnold) and for scale Z later. In the 1988 miniclub catalogue there were three locos announced with built-in decoders for this DC Digital control system. These never reached the market, later Märklin stated that they had technical problems with the heat dissipation of the tiny decoders.

Since then, nothing official was heard of Märklin again about the connection of Z and Digital. This is a pity, because while full digital control with built-in decoders in locos does not seem to be possible yet, other possibilities are interesting enough to be explored!

I am especially interested in controlling my miniclub Z trains with my computer, in two ways:

Using the computer as one or several control devices (as replacements for Märklin's "Control 80f", "Keyboard", "Switchboard").
Using the computer as a very flexible device for automatic control of train processes.

Macintosh HyperCard Screen

The use of HyperCard on Apple Macintosh is an easy way to self-made computer control software. The HyperTalk programming language is easy to learn, and makes event processing very intuitive. It makes it easy to build a pleasing user interface too.

In their 1987 book, Märklin only dealt with controlling magnetic coil devices of Z (like turnouts, relays, turntable, signals) with their Digital control system.

The new idea for combining miniclub and Digital

is to control the speed and direction of the engines digitally too. This is not possible in scale Z in the same way as for scale H0 and 1, because the decoder electronics do not fit into the really tiny Z engines. Therefore I moved the decoder out of the locomotive, between the outlet of the Control Unit 6021 and the rails. This allows digitally controlled engine speed and direction, of course as well via "Control 80f" or "Control Unit" as from a computer, connected via the "Interface". But it allows only one train to be controlled simutaneously on one segment (block) of the tracks, just like conventional control. (© rm Jan. 1995)

The advantages of this scheme outweigh that drawback easily:

Uses the same control devices like scales H0 and 1.
Uses one standard "c81"-decoder per track segment.
Allows for direct interactive playing with "Control xy" or Computer playing software.
Allows the usage of computer for programming of complex automatic processes.
Works of course with any existing unmodified Märklin miniclub locomotive!

Principle connections for digital control of train speed and magnetic devices

The schematics show the principal connections for the realization of this idea, and show a solution to the problem of different operating voltages too:

The Z locos want 8 Volts, the Digital devices need 16 Volts. This is achieved by using a booster (with 10V transformer) to drive the locos via the rails, while supplying usual 16V to the Control Unit.

Digital-Macintosh Interface

Connection of the Märklin Interface 6050/6051 to the Macintosh serial port. Note the short circuit between pins 4 and 8 of the Mac port (RS232 <-> RS422 conversion).

The settings of the DIP switches (back of the 6050/6051 Interface device) are shown on the right. (For connection of other computers, refer to Märklin's documentation.)
Please note that according to email discussions on the Märklin mailing list for some users all DIP switches have to be in the ON position in order to work correctly. For me, only the setting shown above is OK (tested with three Macs: Macintosh SE 4/40, PowerBook Duo 230 12/80, and Performa 5300 32/1.2G).

Duo controls H0 layout
Here the PowerBook Duo running HyperCard is connected to the Interface 6050 controlling a H0 layout.

Scale Z and Scale H0

H0 and Z comparison.

Scale Z in Action

The crane waggon of Z (MPEG movie 131KB).

The Alaska F7 and Santa Fe F7 (MPEG movie 1.7MB). Some clips of two F7-powered trains, which are controlled by a computer via Märklin's DIGITAL control system.
NEW! The same movie in QuickTime format with CinePak and Sorenson compression (1.7MB) and with original sound is here.

The Digitally controlled BR03 and 151 (MPEG movie 300KB). The short movie demonstrates the smooth and continuous acceleration and slowdown of software controlled trains in scale Z.
NEW! It is available as a QuickTime movie (1MB) too.

NEW! NEW!
This clip (1.3 MB) shows my Alaska F7 in scale Z in full color!