SEQLEC 2000    -   7¼"G Locomotive Efficiency Competition
Sutton Coldfield    -   10th September 2000

Although coal consumption is not a major consideration in the operation of our non-commercial miniature railway operations, it is none the less interesting to know how well and thermally efficiently our locomotives can perform. Indeed, to some model engineers it is seen as a challenge to design an engine that will perform comparably or better than that achieved in the best full-size designs. For the 3½" and 5" gauges, IMLEC has for many years been THE efficiency competition where the best designs have battled it out for supremacy. With the growing popularity of 7¼" gauge, it was only a matter of time before a similar event became established for 7¼" gauge locomotives. And so it was that in 1991 the Bristol SME staged the first 7¼" gauge Locomotive Efficiency Competition, which became known as SEQLEC. The event has been held every year since at various venues around the UK, and every event has received excellent support and coverage by the editorial team of "Model Engineer" magazine, and of course competitors. This year, Sutton Coldfield MES had the pleasure of staging the event again, and the pictures and captions below give a brief account of the runs. No doubt a fuller account will appear in Model Engineer magazine in due course.

 For those unaware of how the locomotive efficiency is measured, it is basically a process of measuring the amount of coal burnt during a nominal 30 minute run and then comparing this to the useful work done by the locomotive in hauling the load around the track. The energy input to the locomotive is determined by measuring the actual amount of coal burnt during the run, and by knowing the calorific value of the coal used enables an "energy input" value to be calculated. The work done (or output)  of the locomotive is recorded on a dynamometer which functions by integrating the distance travelled and drawbar pull, this is presented as a reading of foot-pounds of work done.  The (thermal) efficiency of the locomotive can then be determined by :

                     Work Output (as measured on the dynamometer)
  Efficiency = ---------------------------------------------------------       x  100%
                     Work Input (derived from amount and CV of coal used)

Two types of coal were made available for the event, anthracite and an imported South American lignitous type of coal. As it turned out  everyone chose to run with the latter type, which although having a fairly low calorific value burnt with a very hot firebed, but produced long yellow flames and left very little ash or clinker residue. Plenty of top air was ideally required for complete combustion, but when this was not provided smoke (sometimes a fog!) could be observed emanating from the chimneys. We were slightly mischievous in providing this coal as we thought it would provide some "atmosphere" whilst still enabling good steaming.    

The action........         (click on pictures to download larger view)

The results........

(All competitors used coal from the same source (of South American Lignitus type) having a heat value of 11,600 BTU / lb net)

And finally.......

Congratulations to John Dalton with another convincing win.
Our thanks to all the competitors who supported this event, who we hope enjoyed themselves as much as we did. Although the competition is by it's very nature competitive, it also a fun event, and once again the good humour was very much in evidence. Thanks are also due to Mike Chrisp and Model Engineer magazine for the ongoing support given to the various model engineering societies that has enabled this to continue as an annual event. Finally, thanks to the members of Sutton Coldfield Model Engineering Society for their help in staging this event, more than 30 members being directly involved on the day!

Now, who's staging the event next year I wonder ?

Report by Peter McMillan
10th September 2000
(Updated 29th Sept)