Biggest ever challenge

Over the last weekend in June, around 200 people, including many eminent railway engineers, gathered at the Stapleford Miniature Railway near Melton Mowbray for the annual Institution of Mechanical Engineers (IMechE) Railway Challenge. This event, organised by the Institution’s Railway Division, was first held in 2012 and requires young engineers to design and build a 101⁄4” gauge locomotive that is subject to various performance trials.

The competition is open to apprentices, students and those within two years of graduation. With seven teams, this year’s competition was a much larger event than the previous three events which each had four entries. There were four University teams: Birmingham, Huddersfield, Sheffield and Southampton, and three from industry: Interfleet, TE Connectivity and Transport for London (TfL). The Warwick Manufacturing Group had started to build a locomotive but ran out of time.

The Stapleford Miniature Railway is operated by the Friends of the Stapleford Miniature Railway (FSMR), and this year’s event presented them with the real-world problem of rail capacity management. Outside the station area, the railway has two miles of single-line track with a balloon loop. On the day of the trials, four trains had to be managed at any one time: two trial locomotives, a rescue locomotive and a steam hauled train for spectators. To manage this, the FSMR produced a manual specifying how the 89 planned train movements would be managed.

Making it happen

Arranging this event is a challenge in itself. For the Institution’s project manager, Rachel Pearson, planning and preparing for the event was a significant task. It included a site visit to Stapleford to confirm arrangements with the FSMR and dealing with an increased number of visitors. A great deal of thought went into the development of the technical specification and challenge rules which are changed each year to encourage innovations and present fresh challenges to previous entrants.

During the weekend, chief judge Bill Reeve presided over six other judges and six scrutineers. The FSMR also fielded a full team to operate the railway. This included the provision of a controller who only accepted movement requests from the Institution’s Railway Challenge controller.

The plan for the weekend was that scrutineering and testing would take place on the Friday and Saturday. Saturday was also the day for the team’s business case presentations and a new maintainability challenge during which teams were timed as they remove and replace a powered wheelset. For locomotives that had passed scrutineering, Sunday was the day of the trials when their performance against the track-based challenges was assessed.

Setting the standard

The Railway Challenge’s technical specification is written to give the teams the greatest possible flexibility to meet the specified performance requirements. It also obliges them to provide drawings, calculations and a system safety analysis to validate their design. Specific requirements include refuelling in 90 seconds, 95% of materials being recyclable, remote operation from the trailing load, provision of an energy meter and the preparation of detailed drawings and maintenance manuals.

Before they can compete in the trials, each locomotive must collect a set of six stickers issued by scrutineers who assess the locomotives and associated documentation for compliance with the specification. These stickers are: Demo, Safety, Fuel, Brakes, Calculations and Indication.

The rules for the challenge award points in eight categories. Six of these are track based: Energy Storage (300 points), Energy Efficiency (300), Traction (150), Ride Comfort (150), Noise (150) and Maintainability (150). There are also two presentation challenges – for a business case presentation (150) and design report (150).

The rules state that the objective is to challenge teams to build a locomotive and to compete against other teams in a series of challenges. However, the real objective is to develop young engineers and attract them to the rail industry. Wesley Gilbert, TE Connectivity’s global rail marketing manager, has no doubt that the Railway Challenge meets this objective. He feels it provided his graduates with “a unique opportunity to learn from real project management experience in a multi- disciplinary environment”.

It was Professor Simon Iwnicki, director of the Institute of Railway Research at the University of Huddersfield, supported by fellow members of the IMechE’s Railway Division, who pioneered the idea of the challenge. He also has no doubt that the challenge “develops broader skills including time management on a big project, working together as a team, sharing out tasks and overcoming technical challenges in tight time constraints”.

The teams and their locos

New entrants to the challenge this year were the Universities of Sheffield and Southampton and the Swindon-based TE Connectivity. The Sheffield team consisted of first and second year mechanical engineering students led by David Roebuck. Their locomotive was powered by a petrol power pack. It had a low, below- axle bogie frame and did not have an energy recovery system which is being developed for the 2016 challenge.

The Southampton team, led by Mitch Clark, was made up of 12 final-year mechanical engineering students. According to Mitch, their biggest challenge was that they “were all mechanical engineers”. Despite this, they had developed a hybrid locomotive which used a modestly- powered 2.8kW petrol generator, super-capacitor and batteries to deliver a peak 14kW output with a ‘get you home’ facility. The remote Wi-Fi control system could control the locomotive from up to 100 metres.

TE Connectivity had a team of six graduate engineers led by Matthew James. Their locomotive was a four- wheeled locomotive with rubber bush suspension. Its control system used a Raspberry Pi computer whilst an Arduino platform was used to monitor sensors for condition monitoring.

Interfleet was the winner of the first challenge in 2012 and has participated in every challenge since. Its team was made up of seven mechanical and electrical engineers who joined the company in August, led by Peter Bryant. This locomotive was also a hybrid with 3.6kW peak power. Due to its aluminium construction, it weighed only 380 kg.

The University of Birmingham’s four-wheeled locomotive was powered by a 4.5kW hydrogen fuel cell. Another novel feature of this locomotive was its silicon carbide inverter. Ivan Krastev led their team of ten students.

The University of Huddersfield locomotive won the challenge in 2013. This year the team was made up of eight final year students, led by Eduardo Samuel Matthew, who had each undertaken projects to improve the locomotive. This included the provision of a secondary air suspension and a more reliable design of their unique axle-mounted coil spring energy recovery system.

Last year’s winner TfL fielded a team of nine graduates and nine apprentices led by project manager Bejal Mandalia. Their locomotive had an innovative hydro-pneumatic energy recovery system. Since last year, the locomotive had been rebuilt to a new lightweight design to reduce its weight from 1000kg to 532kg.

Fried Raspberry Pi

On Friday and Saturday, the locomotives were subject to the various scrutineering tests. The teams also tested their locomotives on the Stapleford railway. Unfortunately, despite much hard work, three teams were unable to pass scrutineering or operate reliably and so did not participate in Sunday’s performance trials.

Under load, the spikes from the output of the generator of TE Connectivity’s locomotive burnt out its Raspberry Pi computer. The team had to go to Coventry to purchase a replacement. Once this was repaired, the traction motor drive was affected by play in the axle box suspension bush.

Birmingham’s locomotive also suffered various electrical problems, in part from under-specified components. After one channel of the chopper control burnt out, the locomotive was run on a single traction motor that failed as it returned from a test run on Saturday afternoon. After working late into the night, the motor was replaced and scrutineering completed. Unfortunately, the locomotive suffered a further electrical problem on Sunday morning.

At first, the testing of Sheffield’s locomotive seemed to go well, but on return, it derailed on the sharp curves in the station area. It became clear that this was not an isolated problem and the locomotive was deemed unfit for the trials. The Sheffield team were determined to participate and so worked through the night to modify the suspension. Although the locomotive passed scrutineering at 08:15, it later became clear that it was still prone to derailment.

Saturday’s challenges

For the business case challenge, teams have to consider themselves as part of a design consultancy that wishes to sell its prototype 101⁄4” gauge locomotive to a ‘large corporation’. The aim is to evaluate the team’s ability to show how its design best meets the customer’s demands and is cost effective. This can be a tough challenge as it requires teams to ask themselves why anyone should want to buy their locomotives when they have spent months focused solely on engineering issues.

New this year was the maintainability challenge, which tests the ease with which a major component can be removed and replaced. Each locomotive had to move under its own power to a point where a powered wheelset was completely removed and re-fitted. The winner would be the team with the shortest time, subject to any penalties for safety infringements.

Sunday’s winner

Of the four teams that completed Sunday’s performance challenges, the winner was TfL, the first team to win in two successive years. Interfleet, University of Southampton and University of Huddersfield took the second, third and fourth prizes. Although they did not compete in the trials, TE Connectivity, Sheffield and Birmingham took fifth, sixth and seventh prizes from points awarded for their business case presentation, design report and the maintainability challenge.

Before announcing the results, chief judge Bill Reeve emphasised that he was impressed by the teams’ “consistent application of commitment, ingenuity and sheer hard work”. He expressed a special welcome for the three new teams who, he felt, were to be congratulated “just for showing up” as producing a new locomotive in such a short time was a real achievement.

He noted that the challenge involved trying new technology and that new ideas do not always work first time. This was not just a problem for competitors. For the judges, it had proved impossible to assess this year’s new energy efficiency challenge fairly.

Bill promised that next year there would be clearer guidance on this challenge, which is a hugely important part of railway engineering.

Fun and learning

The Institution’s president, Professor Richard Folkson, presented the winner’s trophy. As a former chief judge for the Formula Student competition, he was impressed how the Railway Division had developed its own industry equivalent. He acknowledged it must have been disappointing for some teams to have worked hard on their locomotives and not get the opportunity to run in the trials but encouraged them not to feel downhearted. He was sure that they had learnt a lot and felt everyone had a lot of fun over the weekend.

The participants at next year’s challenge will be almost all new, as the challenge rules do not allow any team to have more than two team members from a previous railway challenge team. Hence, no doubt, many lessons will need to be re-learnt next year. Having reported on the challenge since 2012, Rail Engineer would like to think that future challenge teams would find our articles about it to be useful and would like to offer the following tips for success:

• Test your locomotives before the challenge on one of the UK’s fifty 101⁄4”-gauge railways. Under power, they get hot, vibrate and generate electrical spikes. The only way to be sure it will stay on track is by running it over points and tight curves.
• Understand the limitations of standard components such as chains. It is not wise to use electronics rated at a maximum 48 volts in a 4 x 12 volt battery system that may reach 53 volts.
• Effective project management is essential. Particular aspects of the locomotive may be the result of a number of successful student projects that need to be co-ordinated to ensure on-time completion. Know when to freeze the design and ensure that materials are effectively procured.
• Make a good business case presentation that includes engineering, reliability, cost and other benefits that would make someone want to buy the locomotive. Having spent so much time solving the locomotive’s engineering problems it can be difficult to see things from a customer perspective.

You ain’t seen nothing yet

At a time when the rail industry is suffering from a critical shortage of engineers, the IMechE’s Railway Division is doing its bit to attract and develop young talent. The success of the Railway Challenge was evident from the enthusiasm of everyone concerned and the smooth running of the event, in no small part due to FMSR which is also short of engineers. Please contact them if you would like to volunteer to work on the Stapleford Miniature Railway.

With around forty universities offering rail engineering, and numerous rail suppliers, there is significant potential for more entrants. Current Railway Division chair Chris Kinchin-Smith advised, “You ain’t seen nothing yet”. He promised that the Division would grow the competition and thanked teams, not only for their huge achievements over the weekend, but also for helping the competition grow through word of their successes.

It seems certain that the Railway Challenge will continue to produce more innovations on 101⁄4” gauge locomotives. It remains to be seen whether innovations first trialled at Stapleford might eventually find their way onto a standard gauge railway.