Working with Station Road Steam Ltd, the Taylor Kellar Partnership has developed a 21st-century equivalent of James Watt’s Indicator.

A small electronics module, designed and manufactured as a joint venture, is controlled by an Android app on a phone or tablet.

Indicator system

When connected to monitor cylinder pressure and piston movement, the system displays a traditional indicator diagram in real time,
automatically calculating the Mean Effective Pressure and the Indicated Horsepower.

This sequence of three charts, taken from Station Road Steam’s ‘Stafford’ on a rolling road,
show correct behaviour of the Walschaert’s valve gear as the engine is notched up
–  as well as small crosstalk effects from the other cylinder.

Figure 7 Figure 6 Figure 5

The system’s dynamometer capability can be used to display Brake Horsepower during an indicator trial,
and has also found a very successful application for stand-alone dynamometer use.

Storing up to one hour of distance/drawbar readings, the system has become the dynamometer of choice for IMLEC,
the International Model Locomotive Efficiency Competition.

The system was first used for the 2013 IMLEC at Leyland SME,
and also for the 2014 IMLEC, at the Bournemouth and District Society of Model Engineers.

For the 2015 event, the Nottingham Society of Model Engineers used our system for their new Dynamometer car.

This chart shows John Cottam driving LNER P2: 2-8-2 No 2006 ‘Wolf of Badenoch’.
In spite of a couple of derailments, he was this year’s winner, repeating his success from 2014.

Dynamometer 2015

We like to think that this development would have pleased Richard. Not for the first time, we have applied modern engineering to a traditional problem,
both maintaining the traditional look-and-feel and adding much in the way of facilities targeted at a very specific operational need.