On a very hot 25 June, vans loaded with miniature locomotives, each weighing approximately three quarters of a tonne, started arriving at the Stapleford Miniature Railway (SMR) near Melton Mowbray in Leicestershire. By the time your writer (deputy head judge and scorer for the competition) arrived on the following day, over 200 people were on site, and scrutineering was in full swing under gazebos positioned around the turntable, commissioned in 2025.
The IMechE Railway Challenge, now in its 14th year on site (and online-only during the pandemic restrictions in 2020), encourages teams of young engineers, including apprentices, undergraduates, and graduate trainees, to design and construct a 1/5th scale locomotive to run on the 10¼ inch gauge railway which is nearly two miles long.
Teams undertake many challenges, most of which have a paperwork as well as an operational element. Building a new locomotive from scratch in a year is, for students doing the work as a part time activity amongst other studies, rather challenging. There is now also an entry level competition which allows these teams to compete based on paperwork submissions.
Full-scale replication
The competition is designed to replicate what engineers might experience if they were involved in a full-size train manufacture with each element having a full-scale equivalent.
Details of the challenges are in Table 1:
Along with the challenges, teams are required to submit method statements and risk assessments for their work on the locos, especially when unloading and loading them into road transport and when lifting them for the Maintainability Challenge. This year, 12 Full and two Entry Level teams entered, although one Full Team withdrew and another was unable to complete its locomotive in time.
Back to the Thursday delivery day; some teams were unloading on a new ramp/raised track leading to the turntable from the delivery area. Others were using ramps on the vans or using tail lifts for parts of the locos. This is one of the riskiest tasks of the whole challenge, hence the method statements requirement and close observation from IMechE volunteers.
While the Design Challenge requires teams to demonstrate compliance with the Technical Specification, scrutineers double check compliance against the physical locomotive, checking gauge compliance, static brake performance, and various other safety requirements. Once successfully completed, the loco is coupled to two SMR carriages, for a dynamic brake test run and speed check. Locomotives that can carry a driver are subject to more scrutiny to ensure they are stable when a typically 75kg driver is on board who may alter the dynamic performance of the locomotive and will raise the centre of gravity.
Once a loco has passed static and dynamic scrutineering, it can enter the Maintainability Challenge where the teams remove and replace a motored axle safely. The fastest team, at just over 38 seconds, was 20 times faster than the slowest!
Saturday brings more Maintainability Challenge attempts and, often, more scrutineering. The Autocoupler Challenge (optional) takes place, and each team is given a slot to practice the track challenges that take place on Sunday. Saturday afternoon brings the three best Business Cases, previously given online, in front of the judges live. In addition, the teams with the top three Innovation papers can pitch their ideas to the panel.
The timetable
By the end of Saturday, six locos were confirmed to be working ready for the track challenges. Sunday morning was fortunately cooler, and a seventh loco, which had been repaired following an earlier mis-connected battery which damaged some electrical circuits, was added to the schedule. The outline Challenge timetable, run using the full signalling of the SMR, is as follows (see the map of the site)
A passenger train runs around the loop stopping at the home signal for Train 1 to pass prior to rejoining the single track at the Haven.
Approaching the Haven, Train 1 performs the Autostop Challenge. A beacon on the track at Point A tells the loco that it must stop automatically within 25 metres. The best team achieved this within 45mm!
Train 1 sets off from the station and is followed by SMR’s own ‘diesel’ loco which can be used to rescue failed challenge locos.
Train 1 moves onto the bridge over the stream and stops while the Ride Comfort measurement kit is fitted. The diesel follows.
The passenger train returns to the Station.
Once the passenger train has returned, Train 2 sets off from the Station.
Train 1, shadowed by the diesel, sets off for the Ride Comfort Challenge around the loop, stopping at the Spillway Bridge. The winner achieved 1.05 NMV, the best ever result.
Train 2 proceeds to the Autostop Challenge, and then onto the bridge.
Train 1 runs forward to the Energy Challenge and brakes to a stop harvesting energy. Once given permission from the judges, and the home signal is clear, the driver attempts to move using only the energy harvested in the last stop. The distance travelled is measured by the judges with the best team motoring/coasting for over 47 metres.
Train 1 proceeds to the Traction Challenge – timed over a 15-metre section from a near standing start and then travels to the station. The best loco covered 15 metres in 3.81 seconds.
Train 2 sets off on the Ride Comfort Challenge.
The diesel runs forward off the loop and reverses onto the bridge.
Train 2 completes the Ride Comfort Challenge.
Train 2 completes the Energy Challenge.
Train 2 shadowed by the diesel, sets off for the Traction Challenge and then returns to the station.
This cycle is repeated as appropriate to cover all seven working locomotives.
It is hoped that this detailed description gives a flavour of the complexity of the operation which is the result of detailed planning by IMechE volunteers and the professionalism of the members of the Friends of Stapleford Miniature Railway (FSMR) who are the operators of the SMR.
The FSMR staff operate the passenger trains and the signals and provide a guard for each competitor’s train. More than this, the FSMR welcomes the IMechE and the competitors every year and go out of their way to help. FSMR volunteers have made, welded, or repaired many components in their on-site workshop to help a team fix a failed loco.
The results
So how did the teams fare? Track-based challenge results are in Table 2, and team rankings for each challenge and the overall score and rankings are in Table 3.
Five teams had travelled long distances with their locomotives: the university teams from ESTACA-Paris Saclay in France, Fachhochschule Aachen and Technische Hochschule Nürnberg from Germany, and Poznan University of Technology from Poland.
But the prize for the longest journey went to Monash University from Melbourne, Australia whose loco was transported in a rather large crate.
Great Britain was represented by Network Rail, Newcastle University, University of Sheffield, Siemens Mobility, and Transport for London. There were casualties along the way and sadly the ESTACA, Newcastle, and Siemens Mobility locos were unable to compete on the Sunday despite the enthusiastic and professional efforts of the teams. When the competition first began, all but one of the locomotives were powered by petrol generators, the exception being University of Birmingham’s which was powered by hydrogen fuel cell. Gradually, battery power was adopted, and the organisers dropped the noise challenge after realising that the dominant noise was wheel-rail noise.
Now, most of the locomotives are powered by Lithium batteries with a few retaining lead acid types. The batteries chosen are increasingly the Lithium Iron Phosphate type. One of last year’s innovation papers proposed sodium batteries, but none materialised this year. Monash University purchased a second set of batteries in the UK to avoid the restrictions around air freighting lithium batteries.
A variety of electric motors were used: DC commutator, DC brushless, and AC types. Installed power is typically in the region 6kW – 10kW with traction drives including gears, belts, and chains.
The energy recovery challenge remains a serious challenge for teams as they have to demonstrate to the judges that only the energy generated in the stop between points F and G is used when the train motors. Some teams generate into supercapacitors and measure voltage change, others generate into the battery and use an energy meter. This works reasonably well if a suitable size supercapacitor is used but the voltage change is tiny if a large supercapacitor (e.g., 500 F) is used. Of course, the voltage difference regenerating into a battery would be negligible, hence the need for an energy meter.
When the competition started, most teams’ locos looked like boxes on wheels, but over the years, with the development of social media, sponsorship, and some emphasis on looks in the competition, teams have increasingly improved the appearance of their locos. This year’s crop was particularly handsome to your writer’s eye.
Notable were the sleek lines of Aachen’s and Poznan’s locos. Newcastle’s was a pretty faithful replica of North Eastern Railway’s Electric Bo-Bo Class ES1 from 1905. TH Nürnberg produced the Adler loco inspired by a 1835 steam loco of the same name. This year the team added a ride on feature by building a tender for the loco further nodding to the inspiration.
Possibly the most unusual was Monash University’s loco which was made to look like a W-class Melbourne tram (built between 1923 and 1965) with cartoons of native Australian animals in the windows.
The winners
Entry Level teams this year were Universities of Huddersfield and Lisbon. Lisbon was notable for winning places in the presentation finals for both Business Case and Innovation. The latter is a two-part Challenge – paper/presentation and quality of implementation. Without a loco, Lisbon was unable to demonstrate its innovation (carbon fibre/steel composite axles) but won an award for their presentation. Lisbon was also overall winner of the Entry Level competition.
Monash came a creditable fourth with 1,583 points. Head Judge Bill Reeve said this was a very creditable first appearance with the challenge of long journeys, jet lag and, especially, as “They had to learn to walk the right way up”.
The top three were separated by a mere 80 points. From a total of 2,200 points to score, Poznan came third with 1831 points, Sheffield were second with 1,879 and the winners, FH Aachen with 1911 – just 279 points short of the maximum. In time honoured fashion, the winners completed a victory trip around the track with eight carriages carrying 36 passengers. The loco’s maximum installed power was around 6kW, a most impressive performance.
Your writer’s takeaway from the competition was the incredibly professional but friendly atmosphere with great cooperation between teams. This seems to have been enhanced by the working environment around the turntable. Teams were genuinely overjoyed to receive awards at the prize giving hosted by Bill Reeve, none more so than the ESTACA team whose loco was unable to run. The team was presented with a judges’ special award for their sheer determination, working together in adverse circumstances, and their esprit de corps.
Thanks are due to the Friends of the Stapleford Miniature Railway and Lord Gretton, the railway’s owner, for making the whole event possible, to IMechE staff led by Olivia Evans-Walcott, and more than 30 IMechE volunteers working as controllers, scrutineers, and judges.
Image credit: Malcolm Dobell