A Fun Efficiency Competition Sponsored by Model Engineer, for 2 1/2 inch*, 3 1/2 inch and 5 inch Gauge Model Locomotives of not more than 50lbs Total Dry Weight**
On arrival competitors should report to the Control Point, where their locomotive will be weighed and boiler certificate inspected, and all necessary information concerning the days event provided, including the approximate time for the run. They will also be informed of their allocated observer if they wish to carry one. If not, observers will be stationed around the track.
Approximately 45 minutes before each run the driver will be called to prepare their locomotive in the presence of an observer, who will be on hand to offer any assistance required. To encourage both young and inexperienced drivers, any support needed in preparation will be allowed, provided there is not so much as to cause a hazard, or inconvenience to other drivers.
As much charcoal, wood and paraffin as required will be provided for raising steam. The changeover to coal will be at the driver's discretion. However, the locomotive must have a good coal fire before starting the run.
To prevent undue wheel slip and track contamination, drivers are advised to ensure that their locomotive wheels are free from excess oil. The use of working sanding gear is permitted. If the driver so requests the starter will sand the rail ahead of the start.
During the event, drivers shall use only the coal provided by the Organisers, which will be available to them in weighed bags. The coal will be anthracite, in sizes grains or beans as required.
The minimum trailing load for all locomotives shall be a driving trolley and the driver. The trolley may be provided by the driver, or will be provided by the host society if previously requested. If the driver has elected to carry an observer, an appropriate trolley will be added to the train if the driving trolley is not able to carry the observer. All trailing load must be weighed prior to the run. This will be trolley/s, driver, any observer and passenger/s, and any 'dead' load requested.
Drivers may choose the load to be carried, if any.
Passengers or 'dead' load may be offloaded at any time during the run. However, additional load may not be taken on once the run has commenced. Laps that have been completed up to the point at which the load was reduced, will have work calculated to that point. Subsequent laps will be treated as having had the reduced load throughout that and subsequent laps. Total work will be the sum of these calculations.
The duration of each run will be nominally 20 minutes, with a minimum of 15 minutes. The timekeeper will keep competitors informed as to their progress. If the finish is reached before 20 minutes have elapsed, but more than 15 minutes, the driver may elect to stop or to continue for another lap.
Should a driver stop short of the finish area due to shortage of coal, steam or water, even though the full 20 minutes has elapsed, they must recover pressure and complete the run to the finish. If the driver stops on the final lap they will be deemed to have retired after a total time of 25 minutes has elapsed. No time allowance will be made for stops caused by the derailment of the locomotive or for loss of power.
If the run is terminated before 15 minutes have elapsed or if the driver is unable to complete at the finish point, the competitor will be deemed to have retired.
Water and coal will be passed to competitors as required, in suitable containers, so that topping up can be carried out without the need to stop.
Observers will advise the driver if speed is considered to be approaching an unsafe level for the track.
During the measured run, trains must not be assisted in any way. All work must be performed by the locomotive. The use of the hand pump will not result in disqualification. To enable this, work done will be calculated acording to track characteristics and a dynamometer will not be used.
On completion of the timed run, the train will be uncoupled and time recorded. The locomotive will then be run forward to the Steaming Bay area, assisted if necessary. All unused coal will be collected and weighed in the presence of the driver. No allowance shall be made for any unburned coal within the firebox.
Drivers will be allowed to make two runs during the competition, giving them the opportunity to learn the track on the first run and adjust their load accordingly. The start of the second run shall be separated from the start of the first run by at least three hours.
The results will be calculated by the Organisers, and displayed for drivers and onlookers to see. Each driver will be provided with a print-out of the details of their run. Only the best run from each driver will contribute to the final results.
The winner will be the driver of the locomotive returning the highest thermal efficiency, and will receive the Small Locomotive Challenge Trophy, to be held until the next competition, £50 cash, and a one year subscription the Model Engineer magazine. Second will receive £25 cash, and third will receive a £20 Warco gift voucher. Other prizes will be decided by the Organisers.
In the unlikely event of any dispute arising, the decision of the Organisers shall be deemed to be final.
GENERAL NOTES
Total work done by the locomotive will be calculated using the product of the number of laps completed, and the work done per lap. Work done per lap will be derived from the total weight pulled by the locomotive, the known length of lap, known gradients of the track and an assumed rolling resistance of the trolley/s. (Contestants wishing to see the basis for calculation of work done may discuss details with the Organisers). Nominal efficiency will then be calculated from the work done and the coal consumed, based on 1 BTU = 777.6 ft.lb. and coal calorific value = 14,500 BTU per pound. Thus,
Efficiency % = (Work done x 100)/(Coal used, pounds x 14500 x 777.6) = (Work done x 100)/(Coal used, grams, x 63.88 x 777.6)
This method has been chosen so that the host society does not have to provide a dynamometer car.
The need for spark deflectors / arrestors will be at the discretion of the host society.
STANDARDISATION
There has been some discussion at the last two events regarding methods for weighing loads, locomotives and coal. Various grades of bathroom and kitchen scales have been used, mostly analogue types. Unfortunately, unless a lot of money is spent, there is some doubt about the accuracy and repeatability of these. We have therefore decided to create a standard kit that will be loaned to hosts, to use during the event. The kit will comprise a standard 50 pound weight, accurate to plus one ounce, minus zero, a digital scale with a range up to 11 pounds and resolution of 0.125 ounce, and a modified digital bathroom scale with a resolution of 0.1 pounds and full scale of 330 pounds. Tests have shown these scales to be reasonably accurate and repeatable. It is hoped that in the longer term, standard trollies may be introduced, but short term, hosts will be encouraged to ensure free-running trollies are provided.
*2 1/2 inch gauge locomotives will be admitted to the competition if the host society has a suitable track, if the event is not already fully subscribed.
**Dry weight is the total weight of the locomotive including it's tender if it has one, but excluding coal and water. Any ballast used to add to the weight of the model must be included in the dry weight.