A report on two TCS members' exploits at the Cardiff Model Railway Exhibition in March 2006.

Two TCS members joined forces with their friends in the BBC (Cardiff) Model Club to provide an exhibit entitled, Model Railway Electronics Old and New. Several of the members are also members of MERG  (The Model Electronic Railway Group). The idea of the exhibit came from the increasing interest in DCC and the wish to simply explain it to the general public and an idea to run one of the original Multiple Train Control analogue systems. The Airfix MTC system was introduced in 1980 and used 20v AC on the track with a superimposed control signal. Unfortunately it was only produced for about 18 months when Airfix went into receivership and the concept was not developed but dropped.

To simply demonstrate the systems it was decided to have an outer oval of track running DCC and an inner oval running Airfix MTC. The Bachmann DCC setup was based on their 'E-Z Command' system Freight Set, and as expected worked straight out of the box with any Loco and make of chip we tried. The Airfix was another matter alltogether.

The Stand at the Cardiff Model Railway Show 2006

The Airfix MTC Controller

My Airfix MTC interest had begun as part of the research into the Airfix Web Site and I had acquired various locomotives and was fortunate to pick up three boxed, unused, MTC Controller Sets each containing a main controller, two hand controllers and two locomotive modules. Easy I thought to show a simple system.

Controller 1 was tested and found to have no output, fortunately one of the members of the BBC Club is an Electronics Maintenance Engineer and he got stuck in. Faulty rectifier was diagnosed and replaced, still nothing. Unit was dismantled  and found to have a broken circuit board no amount of repair to copper strips etc could get it to work, static display piece I thought.

Controller 2 when removed from its new packing was found to have all the switches stuck in the off position and would require considerable work to repair.

Controller 3 proved to be a better proposition and seemed to give an output although one of the hand controllers would not work.

The Show setup DCC on the outer track, Airfix MTC on the inner.

One of the computers ran a presentation explaining the set up, the other one carried a slide show of pictures of earlier power units.

A control module was fitted on the bench to an new boxed, Airfix Prairie. As the instruction said easy, until you tried replacing the body, the modules seemed to have grown over the years. The simple job took 90 minutes and then it didn't work. This proved to be the loco itself being faulty and a full overhaul and service was required to bring it to life. The tuning of the module in the loco to the channel on the controller was fairly straightforward and at last the loco moved on the track to the biggest shower of sparks from the wheels I have ever seen. After much cleaning and adjustment this settled down and we had one loco that ran fairly well under MTC.

Two more locomotives were fitted with modules, again physically not an easy task. These ran much better than the Prairie and the 4F became the main loco with occasional outings of the Royal Scot

What about the two locos running together on the same track? Straight forward we thought, until we tried it. Every time we increased power to the stationary loco the loco that was running slowed and stopped. Couldn't think of any reason for it other than we had left the capacitors fitted by mistake to the locomotives when the instructions said to remove them. The locos were stripped down and the capacitors removed. Disaster both stopped working properly and became intermittent. Capacitors replaced and the locomotives started working again, so much for following the instructions.

We never got the two locos to work together on the same track, this is the next part of the project. If anyone has any experience of this system please let me know.

Showing some of the modules used for the display.

‘Any make, Any gauge, Any age’

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