A core element of my interests lies in the application of technology to model railways.

Elsewhere I’ve discussed my personal history and my experiences but not really addressed the role of technology change in all of our lives, especially the life of the model railroader / railway modeller.

30 Years ago, the modeller had one main choice for operating trains – DC power varying in amplitude to control the speed of the train.

DC / AC Powered Railways

The simplicity of a DC or AC powered model railway where the track voltage controls the speed of the motor has many excellent features that make it an ideal approach for the control of model trains in their many and varied locations.

The hobby standardised at an early stage on a 12V DC ‘standard’ which probably has more to do with the turns ratio on transformers from AC mains supply than it does from any true attempt to achieve an industry standard (anyone out there ever looked into this?).

Combined with track gauge/scale standards, this allowed models from multiple suppliers to be run on a single model railway.

The downside of the DC approach is that only one locomotive can be run per controller, or at least more than one loco but all locos will run in the same way. No independent control.

For UK and European modellers, this was not much of an issue as most trains ran with (still do) a single loco, but for North American modellers this has been a challenge as most trains there run with multiple locos, often split across the length of the train – double-heading with bankers (or distributed power).

In order to run multiple trains across a layout, model railways were divided into separate electrical sections (blocks) each with separate switches allowing multiple controllers to be able to have control of a block and therefore allowing multiple trains to run completely independently.

This style of wiring and control is often called ‘Cab Control’ because it gives the feeling of controlling each train independently. I’ve wired many layouts in this style – often following the owners attempt to wire it themselves and then finally giving up after getting hopelessly confused. (See separate piece on Layout Wiring).