Railway Challenge


Railway Challenge - Your questions answered

FAQs 2021

Technical specifications/rules: regenerated energy

It has been brought to my attention that for the energy storage challenge last year, contrary to the technical specification, the regenerated energy could be directed back into the primary traction system, provided that it could be shown that the energy going in and out was the only energy used during the challenge. Is this still the case for this year's challenge?


We have updated the Technical Specification to allow regenerated energy to be directed back into the primary energy storage system provided that all other clauses in the rules and technical specification are met.

Technical specifications/rules: team members

Given the issues with COVID-19 and the nature of the competition from last year, where many teams did not build their locomotives is there potential for waiving the rule for 2021? 

No team may have more than 40% of its team members who have been members of a previous Railway Challenge team.


Due to the COVID-19 pandemic, this rule has been waived for the 2021 competition. The 2021 rules were updated on the website.

Technical specifications/rules: Drawings - loading gauge

Does this loading gauge drawing take into account the 20m minimum radius for the whole locomotive in terms of centre throw?


This is a kinematic envelope, the standard method of specifying loading gauge. It defines the dimensions of the railway, not a locomotive. To fit into the kinematic envelope, the design of a locomotive needs to factor in not only the maximum cross-section but its end-throw, centre-throw and movement (primarily re. suspension). The maximum locomotive cross-section will be notably smaller than the kinematic envelope. It will vary from vehicle to vehicle, depending on longitudinal dimensions (e.g. overhang, length between bogie centres etc.) and suspension characteristics.

Test track: the type of materials used for the sleepers, the depth of the ballast

We are planning to make a test track for our locomotive but for that we needed some information about the type of materials used for the sleepers, the depth of the ballast. We would be really grateful if we could find some information regarding this.


The railway track at Stapleford is constructed in different ways in different locations with varying rails and sleepers and fixings and welded tie bars so it is not possible to give a specification that would be representative of the whole route.

Several universities have constructed test tracks and we would be happy to put you in touch with these so that they can share details of their construction methods.

Traction Challenge: head of the rail width

How wide is the head of the rail at the location where the Traction Challenge takes place?


Traction Challenge: The rail used at that location is probably either S7 or 18lb/yd (which is slightly larger and heavier). A drawing of the S7 section is available here: http://www.miniaturerailwaysupply.com/rail/s7steelrail.htm

Although you should be aware that there may be some wear and the profile of the rails may vary slightly along the track. The width of the head of the rail is therefore around 25mm or possibly up to 30mm in places.

Why do I have to pay to formally register?

The team registration fees are used to help the Institution cover the running costs of the Railway Challenge. The student challenge portfolio is expected to break even and that is one of the reasons we engage industry partners who help us finance the competitions annually.

All participants are expected to pay the registration fees and many teams engage with local companies and have managed to secure sponsorship that helps them to cover the costs.

The IMechE helps provide funding via our grant schemes.

FAQs 2019

Auto-Stop Challenge: lineside markers

As part of the Auto-Stop Challenge where we have to place a lineside marker on point A and 25 m further bring the loco to a stop - are we allowed to place a sign on Point B (where the loco has to stop) too? Or is there at Point B no detectable marker provided/allowed? I couldn't find some information how Point B should be designed.


All lettered points according to the rules, including point B, will be indicated by the organisers using a board adjacent to the track. For the auto-stop challenge, teams are 
required to provide the marker to be detected by the locomotive at point A, which will also be indicated by the organisers using a board. The board at point B will only be for reference, and the locomotive’s braking system should be designed to enable it to 
automatically stop as close to this point as is possible without intervention from the
team in line with rule B6.5.

Auto-Stop Challenge: lineside markers positioning

For the Auto-Stop Challenge how will the lineside distance marker for each team be positioned?


Each team provides their own location marker device. A nominated team member (not one of those on board their train) will position this at Point A (as indicated by a lineside marker provided by the challenge management team) when instructed by the IMechE judge / marshal. Positioning of the device (and fastening if required) shall be completed within three minutes. Removal, after the train has passed, must be completed in no more than two minutes.

Locomotive design: final drive chain

Is it acceptable for the final drive chain to remain around the final drive sprocket, which is on the wheelset axle, when the wheelset is removed, provided that the chain is not too long?


Yes, there would be no objection to this as long as the chain does not in anyway cause a hazard.

Ride Comfort Challenge: ride comfort testing

For the Ride Comfort Challenge, what piece of equipment do you use to test the
ride comfort? I assume it is an accelerometer, but I was wondering which one
so that I could use the same for our testing?


The Ride Comfort Challenge will be run in accordance with the rules for that
Challenge. In theory at least, the result should not depend on the test measurement
equipment used if specified and configured according to those rules. Test results will
also be dependent on other factors, e.g. track characteristics) which may render results
from a team’s own testing different to those obtained at the competition. However, we
can confirm that a Larson Davis HVM100 meter is normally used for this Challenge in
conjunction with a Larson Davis SEN027 tri-axial accelerometer. However, the organisers cannot guarantee that this equipment will be used in 2019.

Technical specifications/rules: Changing wheelsets

In the Rules it says that we have to change a driven wheelset. Is it also allowed to change a driven wheelset as a complete unit with the motor together?


The powered wheelset must be completely removed from the locomotive. The wheelset when removed must consist only of the wheels and axle plus axle boxes, brake disks and the final part of the traction drive for example a gear/pulley or sprocket where attached to the wheelset. Other parts of the traction drive including the traction motor must be disconnected from the wheelset.

Technical specifications/rules: Lineside distance marker

Is it acceptable for the ‘lineside distance marker, provided by the team’ (Rules 2019, clause B6.2) to be positioned between the rails, provided it is outside ofthe gauge? The wording in B6.2 states that the marker ‘will be positioned adjacent to the track’, however we were told that placing it between the railswould be fine?


Yes, it is perfectly acceptable for the team’s distance marker to be positioned between the rails, provided it is outside the structure gauge. The lineside distance marker referred to in the Tech Spec is a location marker set up by the IMechE.

Tech Spec section 5.5 states: “Teams will be expected to provide and temporarily fix a detectable location device of their choice at the location of this marker. This device will be designed such that it is entirely outside the structure gauge limits (Drawing RC02 refers)”

Technical requirements/rules: recycling

“Clause 4.2.3 states that the team shall demonstrate 95% of components by mass can be disposed of in such a way that facilitates recycling” does this include reusability (reduce reuse recycle)? Our batteries powering our locomotive are borrowed from an electric train company, who we plan on giving them back to afterwards, they won’t be recycled.


All you have to do is show that they can be recycled, not will be. You need to research what happens to batteries of the type proposed when disposed of – land fill always (not ok) or potentially broken down and elements salvaged (ok).

Technical specifications/rules: tractive effort

Technical specification point 5.7 - A new requirement has been added stating: “Tractive effort applied”. Is this to be a continuous quantification of the amount of tractive effort applied similar to that of the energy storage indicator, or a binary indicator showing when traction is being applied regardless of the amount of tractive effort.


The tractive effort indicator needs to indicate whether the primary power source of the locomotive is providing traction or not. It is not necessary to indicate the amount of traction being applied. This is related in particular to rule B2.5 which states ‘…the primary power source of the locomotive must be disengaged from the drive wheels…’

Technical requirements/rules: Wheelset design

A recently answered FAQ states, with regard to the Maintainability Challenge, that ‘The wheelset when removed must consist only of the wheels and axle plus axle boxes, brake disks and the final part of the traction drive for example agear/pulley or sprocket where attached to the wheelset. Other parts of the traction drive including the traction motor must be disconnected from thewheelset.’

Our team have designed a gearbox where the motor and axle are integral parts, making detaching the motor from the axle impossible outside of a workshop. The motor would be disconnected electrically and removed with the wheelset for the maintainability challenge.


It is not acceptable for the traction motor to be part of the wheelset removed in the Maintainability Challenge. The only non-rotating parts of the wheelset permitted are the axelebox casings (including bearing outer race, etc.).

Separate note to this team on this point: Separate note to teams on this point: The application of this rule has not changed and no previous team has been permitted to remove a traction motor together with the wheelset as one part. Where the design of locomotives has required the removal of a traction motor initially, such as the removal of a bogie which contains an integrated traction motor, then a driven wheelset has still needed to be removed from the bogie before the time is stopped.

FAQs 2018

Challenge course: hiring track for testing ahead of the Challenge

Do you allow track to be hired for testing vehicles? We are looking for some 10 ¼” track to test our vehicle?


It is not generally allowed for teams to have access to the railway track other than for the Challenge itself. This is mainly to avoid disturbing the railway but also as it could give an unfair advantage to other teams.

However, there are many 10¼” railways where you could test your locomotive.

Challenge course: Information to aid the design process

Would you be able to facilitate us with some information about the course to aid
in our design process? Do you have a measure of the roughness of the track?

No, we do not have this information. If you would like to measure the track irregularity
or the rail roughness please contact us and we will try to make arrangements for you to
have access to the railway to make the measurement. Please note that you would need
to supply any required equipment and provide a method statement in advance.

Document submission: length of report

The design report can be no more than 12 pages, excluding appendixes, does that 12 pages include the executive summary or is it just 12 pages for the main body of the report?


There is no requirement for an executive summary. If you choose to include one, it does not have to be included within the 10-page limit but teams should note that only the 10 pages and appendices will be marked. Other material - title pages, contents list, executive summary etc. - is seen as supporting only.

Team: How many members in the team?

How many team members can a team have?

Answer: The overall team size is capped at 15. During the event the number of team members working on a locomotive at any given time cannot exceed 10.

The team member in charge of safety as required by the rules is included in the 15 team members, but not in the 10 working on the locomotive, as they are to be responsible for ensuring safe working.

Team: Sign off on testing

A Chartered Engineer is required to sign off on the testing done by the team. Can this person be a member of staff from the university?

Answer:  Yes, the Chartered Engineer can be from your own organisation.

Technical specifications/rules: Drawings - what drawings are required?

Clause 11.2.2 appears to say that we only need the top level assembly and warning label  arrangement, but 1.1.5 suggests that we need a lot more detail than the single assembly drawing can provide. The 2017 team interpreted that Improving the world through engineering to mean just the top level assembly then the next level ones, i.e. body, underframe and bogie, but the 2016 team also included many of their fabrication drawings, such as the bogie frame, control arm, traction rod etc. Can you please clarify further what drawings are required – is a top level assembly sufficient?


Please note the following Technical Specification clauses, revised so as to provide clarification on this issue:

11.2.1 Compliance matrix
The Team will produce a compliance matrix providing evidence that all technical requirements within this specification (Sections 1 – 10) have been met on a clause by clause basis. This will include a verified statement with respect to reliability testing (Clause 3.4 refers). Teams are advised to use the compliance matrix provided by the Railway Challenge Committee for this purpose. For each requirement, the matrix should briefly state how compliance is achieved in the design and refer to any relevant drawings (Clause 1.1.5 refers) which may be additional to the Design Report. If full compliance with any requirement is not achieved, details of why shall be provided.

11.2.2 Assembly drawing
In addition to drawings supporting the compliance matrix, the Team will include within its submission:
• A general assembly drawing showing the configuration of the locomotive
• A parts list / bill of materials (Clauses 1.1.1, 4.2.1 refer)
The Team will demonstrate appropriate levels of version control has been applied to the production of all drawings and other design documents.

Technical specification/rules: Energy storage assets

Section 4.1 it says:

“if refuelling comprises the replacement of energy storage assets, no individual such asset shall have a mass greater than 25kg.”

Does that mean if our power system consisted of 6 batteries each weighing 12kg, that would be within the spec?

The type of motive power utilised will be entirely at the discretion of the team, subject to the other requirements of this specification.

This rule reflects the fact that in future real world applications, it is conceivable that independent vehicles (all modes) are refuelled by storage system replacement rather than re-filling (battery, hydrogen storage etc.). The details referred to in this text (25 kg) reflect manual handling consideration. The answer is therefore yes – provided batteries are replaced individually or in pairs (2 x 12 = 24), and that the whole operation takes less than 120 seconds.

Technical specification/rules: Recuperated energy

Are we allowed to store the recuperated energy into our traction batteries and monitor the amount of energy we regenerate to make it accessible to the judges?


Yes, this will be allowed as long as the following conditions are met:

  • The amount of energy recovered must be monitored and clearly displayed and continuously visible to the judges (in line with Rules sections B2.2 and B2.4);
  • There must be a method in place to ensure than only the recuperated energy is used during the energy storage challenge (in line with rule section B2.6 and Technical Specification section 5.2);
  • The methods used to store the energy must be clear and the team must be able to demonstrate these to the scrutineers.

Technical specifications/rules: Traction Challenge - how it conducted

How is the Traction Challenge carried out on the competition weekend? How is the Traction Challenge result averaged? If it’s over a certain distance, can you confirm the distance the measurement takes place?


The Traction Challenge will be run in accordance with the rules. The positions of the points will be indicated on a plan of the railway and provided to all teams in due course.

The distance between points F and G used for the traction challenge (in combination with the noise challenge) will provisionally be approximately 100m up the gradient between the
Haven and the tunnel.

Averaging of the acceleration: this will be measured using a vibration meter which takes successive one second average measurement for the duration of the test run.

Technical specification/rules: Using innovation in wheel design or not?

When sending a wheel drawing to a potential supplier for a quote, the supplier suggested the following to reduce the cost of manufacturing the wheel:

  • Removing the 3.3 mm boss completely, keeping the wheel a maximum of 31.7mm wide.
  • The FAQs state that innovation is welcome, as long as it is compliant with the rules/tech spec/drawing with supporting documentation.

The boss is a given dimension - how far does 'as required' go? This would appear to be part of the technical spec, and non-negotiable?


We encourage innovation but would point out that it is the team’s responsibility to ensure that their design is a) safe and b) meets all of the Railway Challenge rules and specifications. This will need to be demonstrated in their design report.

In response to the specific question about the wheel we would make the following points:

  • The total width of the wheel at track level is clearly defined by drawing RC04 as 31.7 mm (+5/-0) and this is an absolute requirement for compatibility with the track system. It appears that both of the above proposals would comply with this.
  • The boss at the wheelseat is shown with a dimension of ‘3.3 mm or as required’. This can therefore be varied to suit other aspects of the locomotive design.
  • The recess between the wheelseat and the tyre is clearly labelled as ‘optional’ so can be varied to suit other aspects of the locomotive design. There may be issues around manufacturing processes and/or fatigue but that is for the team to consider.

Technical specification/rules: Wheel and axle diameter

Is just the wheel diameter is defined as 38mm or the axle? We would like to design a stepped axle that has a diameter that meets the minimum requirements only at the wheel section.

Answer:  There is no minimum axle diameter specified. It is for the teams to design the axles to suit their overall design and to ensure safe operation. Teams are reminded of the obligation to provide stress calculations, which will be the subject of significant scrutiny in areas of non-continuous section.

FAQs 2017

Entries - entering all the challenges

Would there be any possibility of entering only the design based challenges, and having different levels of competition entry as there is in the Formula Student competition? We would hope to be in a position to enter all competitions, but we are keen to assess whether this is a possibility.

Answer: Teams may enter any of the challenges and there is no requirement to enter all of the challenges although the overall result will depend on the total points scored.

Entries - multiple locomotives

This year we are hoping to enter two locomotives, but the finer details are yet to be finalised, and we may not know about whether the second locomotive will definitely be entered until around February. Would it be possible to hold off on submitting the entry application for this second locomotive until this time?

Answer: Unfortunately, due to operational considerations we can only accommodate 12 running locomotives in the 2017 final. We are hoping to be able to increase this in 2018.

Innovation challenge - what is innovation?

Our team are having a little difficulty in determining what counts as “innovative”. We have discussed this at length and are unsure whether the innovation must be new to the rail Industry or just the Railway Challenge itself. Could you clarify what counts as an innovation?

Answer:  The team may focus on any innovation in their locomotive they wish when preparing the Innovation paper but, as the guidance in the Technical Specification (section 11.3) states, the paper should outline how the innovation improves on a conventional approach and how it may be adopted by the national railway. It would therefore need to be an innovation that is new to the railway industry.

Scrutineering checklist

I was wondering if you would be able to send me a copy of the scrutineering checklist so that I can ensure that the correct safety measures are implemented on our locomotive and that we are safe to compete. Having looked through the technical specification, there are some safety requirements specified but having some form of scrutineering checklist (even if it is from last years competition) will be a big help to ensuring that we have a safe locomotive.

Answer: The 2017 scrutinising checklist is being prepared. The 2016 checklist is available.

Trailing load

2017 Railway Challenge Technical Specifications. 10.1 states that “Performance demonstration will incorporate the haulage of a trailing load of up to 1200kg”. This is an increase of 600kg compared to the 2016 requirement. Is a 1200kg trailing load to be hauled during the challenges in 2017?



Answer: Yes, as specified in the Technical Specification (section 10.1) the maximum weight of the trailing load will be 1200kg. It is not possible to give an exact value of the trailing load from 2016 as it depends slightly on the mass of the 3 people carried in the vehicle but we estimate that it was 600kg. The rules and technical specification are varied each year to introduce new challenges and to reduce the disadvantage faced by new teams.

Wheelsets: non-standard

What requirements will apply to wheelsets of non-standard construction?

Answer: We welcome innovation and non-standard wheelsets and wheels will be permitted as long as all relevant aspects of the rules and technical specification are complied with (eg back-back dimensions, spacing of active faces, maximum axle load, wheel profile etc). For non-standard materials or construction methods etc, designs will need to be supported by relevant safety analysis (component failure) and appropriate supporting calculations.

Wheelsets: removal of a 'driven wheelset'

Does an axle need to be removed from a bogie or does the bogie just need to be removed from the chassis?

Answer: As specified in the rules, a single powered wheelset must be completely removed from the vehicle. Components directly attached to the wheelset (eg brake disks, gears, axleboxes, axle mounted traction motor) may remain with the removed wheelset. For a bogie vehicle the wheelset must be removed from the bogie.

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