TRAIN rig 

The Transient Aerodynamic Investigation (TRAIN) rig is a purpose built facility for measuring the aerodynamics of scale moving model vehicles. The unique facility offers the flexibility to conduct a range of experiments crucial to a detailed understanding of vehicle aerodynamic flows. In broad terms, it consists of a 150m long track along which model vehicles can be propelled, in both directions, at speeds of up to 80 m/s. The facility can be used for all types of ground vehicle aerodynamic investigations, but it could also be used for a wide variety of other aerodynamic investigations.

TRAIN rig video


The Transient Aerodynamic Investigation (TRAIN) rig is a purpose built facility for measuring the aerodynamics of scale moving model vehicles. The unique facility offers the flexibility to conduct a range of experiments crucial to a detailed understanding of vehicle aerodynamic flows. These include, but are not limited to:

  • Slipstream velocity measurements
  • Static pressure pulse measurements
  • Pressures acting on the train using bespoke on-board data loggers
  • The effects of crosswinds at various yaw angles
  • Aerodynamic pressures acting on trackside structures
  • Aerodynamic effects of a train passing through a tunnel and sonic booms
  • The effects of embankments on train aerodynamics
  • The aerodynamic effects due to train design and size
  • Aerodynamic loads affecting ballast flight
  • Pollutant dispersion

Close-up of model train on trackThe large 150 m long facility is essentially a catapult along which, nominally 1/10th-1/25th, scale models can be fired at speeds up to 80 m/s. Additional capabilities includes modelling the interaction of passing vehicles. The advantages of using a moving model rig over a traditional wind tunnel for measuring vehicle aerodynamics is the ability to correctly model the relative motion between the moving vehicle and the static ground.

The TRAIN rig has recently undergone a large £1.5 million renovation as part of the UK Collaboratorium for Research in Infrastructure and Cities (UKCRIC) project. The vision of the UKCRIC is to create, operate and coordinate an (inter)national multi-disciplinary research programme in a partnership between Industry, Government and Academia. The Government has provided £138 million of funding for UK national and local infrastructure (such as transport, water, waste, energy and ICT systems) to be fit for purpose for supporting societal development in a changing world. The project is coordinated by thirteen partners, representing the major university-based infrastructure, civil and construction engineering research groups in the UK.

Model of freight vehicles on a trackThe renovation works at the TRAIN rig have been coordinated in three key strands – building extension works, developing the crosswind tunnel and increasing instrumentation capabilities. A large 45 m extension has been built onto the side of the existing TRAIN rig to allow the crosswind tunnel capabilities to be increased through the creation of a 7 m wide space spanning over 15 m of running track. The new 30 fan return flow crosswind tunnel built into this space offers the capability of a much larger flow fetch and greater flexibility to control the flow characteristics before the running tracks. The extension has also created a much needed new workshop facility. In addition to the main building extension, the main test hall has been separated with walls from the firing and brake zone and the whole space insulated to allow greater climate control in the test hall.
A large part of the UKCRIC upgrades was to increase the scientific instrumentation capabilities. Firstly, the firing mechanisms for all firing tracks have been overhauled allowing for greater ease of use and the ability to fire vehicles in both directions. Major equipment purchases include a LaVision 3-D tomographic volumetric PIV system, capable of measuring flow volumes of 0.5m3, a 48 channel triple wire system and 18 multi-hole pressure probes capable of measuring velocities in 3 dimensions and static pressure. The renovation work has also focused on productivity and ease of use in the facility, which has led to a bespoke designed ‘plug and play’ system to measure pressure making use of the increased number of pressure transducers.

Model of TRAIN rig trackIf you have any questions about the use of the facility, any research ideas or work you would like to commission in the facility, please contact Dr David Soper.

Technical specifications

  • The rig is housed in a purpose built enclosure on the RTC Business Park, London Road, Derby
  • The overall length of the facility is 150 m with a 50 m long test section.Climate controlled test section.
  • Nominal model scale – 1/25th for rail vehicle testing, but larger road vehicle models can be used up to 1/10th scale.
  • Model speed - up to 80 m/s.
  • Propulsion system – two rubber catapults, one at each end of the rig.
  • Track systems - three tracks are provided, two at the standard British railway system track spacing scaled to 1/25th and a third at a wider spacing.
  • Vehicles capable of firing in opposite directions simultaneously and crossing.
  • A 15 m long crosswind flow facility is provided adjacent to the test section to permit tests to be carried out on the effects of winds on vehicles and the influence of winds on vehicle slipstream flows.
  • A wide range of pressure transducers and velocity measuring probes of different sensitivities and types are available for measurements.
  • Particle Image Velocimetry (PIV) systems available to conduct 3-D volumetric measurements.
  • Robust on-board measuring systems to directly measure effects on vehicles.

TRAIN rig model train tunnelIf you have any questions about the use of the facility, any research ideas or work you would like to commission in the facility, please contact Dr David Soper.

Research team

The vehicle aerodynamics research team sits within the School of Engineering as part of the Wind Engineering Group.

The team is led by Dr David Soper, who is also the strategic coordinator for the TRAIN rig facility.
The team also has a dedicated research fellow and a number of PhD students working on vehicle aerodynamics related projects.

  • Mingzhe He
  • Panos Illiadis
  • Anam Hashmi

Train aerodynamics - fundamentals and applications

 Front cover of Train Aerodynamics bookTrain aerodynamics – fundamentals and Applications is the first text to provide a comprehensive overview of the many aspects of train aerodynamics. The underlying philosophy of the text is that to properly address train aerodynamic problems, a fundamental understanding of the flow around trains is required, and that this understanding should be based on full-scale real world data. The first part of the book (Fundamentals) thus sets out basic fluid principles, the experimental and computational techniques that are routinely used, and then presents a detailed outline of the nature of the flow around trains, based as far as possible on full scale measurements. The second part of the book (Applications) then applies these principles to a range of engineering applications.

The book contents are as follows:

Part 1. Fundamentals

  • The historical context
  • Fluid mechanics concepts
  • Testing techniques
  • Computational techniques
  • The flow around trains in the open air 
  • The flow around trains in tunnels

Part 2. Applications

  • Aerodynamic drag
  • Aerodynamic loads on trackside structures, passing trains and people
  • Ballast movement beneath trains
  • Aerodynamic effects on pantographs and overhead wire systems
  • Train overturning in high winds
  • Tunnel aerodynamics issues
  • Emerging issues

The book authors are all leading figures in the field of railway aerodynamics:
Chris Baker*, Terry Johnson+, Dominic Flynn$, Hassan Hemida*, Andrew Quinn*, David Soper*, Mark Sterling*

* University of Birmingham
+ Railway Safety and Standards Board
$ Birmingham City University

The book is available in print and electronic versions. To order a copy please visit:

Latest news

The latest news from the TRAIN rig and our vehicle aerodynamics research team.

The TRAIN rig re-opening event

For up to date news on our research publications, please see the TRAIN rig facility coordinator's research portal:

Dr David Soper research portal

Discover more

For further information, please contact Dr David Soper.