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Tech Forum

January 2017

Trainsformer Needed

I found a bargain at a local thrift store and now have a 1959 Marklin HO Scale train, cars, and track. The set didn’t come with a transformer, so I thought it would be a fun project to build from scratch. Does anyone have a schematic or suggestion for a DIY train transformer they can share?

Alfred Thompson
Kingsport, TN


Boy are you lucky!!! I started collecting Marklin HO scale back in 1962, so a 1959 vintage should be fabulous.

The old equipment had AC motors in them, and the original transformers ran 16VAC to 20VAC. In other words, they were variacs which controlled the speed by changing the voltage to the tracks. This did pretty well, except at the very lowest speeds.

So, there are a number of ways to control the locomotive. The easiest would be to use a transformer output through a potentiometer, driving a 30 or 40 watt amplifier, (direct coupled). This output would directly couple to the track. The center spikes are the Hot, with the rails being the neutral.

A more complicated, (but fun way depending on your skill level), would be to use a PIC microprocessor to PWM a sine wave to directly drive the center rail of the track. Then you would have the most control.

Mark Lampkin
Grand Rapids, MI