Abandoned Victorian railway tunnel converted into supercar test track
A 2.7km stretch of abandoned railway has been successfully converted into a test track for supercars and bicycles.
Stepnell and Tarmac led on the project to convert the Catesby Tunnel in Northamptonshire.
With the capability for 24/7 testing in all weather conditions, Aero Research Partners’ (ARP) Catesby Tunnel is expected to attract the world’s largest automotive manufacturers.
The facility enables testing of aerodynamics, performance – such as speed, acceleration, braking and ride comfort – aeroacoustics, and engine emissions.
Catesby Tunnel is a disused railway tunnel in Northamptonshire on the route of the former Great Central Main Line.
The tunnel was completed in 1897, and was closed in 1966 when the line closed. After lying abandoned and flooded for over 50 years, proposals were granted in 2017 for the conversion of the tunnel into an aerodynamic test facility for road and race cars.
Before the test track proposal was approved, the tunnel had been explored for use as part of the High Speed 2 rail project, as well as being included on a failed proposal to build a freight line from Liverpool to Europe.
Tarmac's role on the project, included laying a specially designed SMA asphalt surface, with specialist PSV 65, 10mm gritstone aggregate. The company was selected by ARP after previously successfully resurfacing the racetrack at Silverstone – home of the British Grand Prix.
Tarmac managing director (Midlands) Rob Doody said: “The seamless way this project was planned and delivered resulted in a truly world-class finish that is amongst the highest known paving standards in the world today.
“The level of paving accuracy has delivered a surface with the exceptional consistency and uniformity needed to meet ARP’s aspiration of producing a world leading aerodynamic test site. It enables automotive engineers to take any surface irregularity out of the equation.”
Doody explained how the supply of asphalt had to be carefully planned to ensure a continuous supply to the paver, while ventilation enabled safe working conditions to be maintained for the paving teams while working in the tunnel.
To achieve the super-smooth finish to the test track required by ARP, Tarmac used specialist aggregate – with a Polished Stone Value (PSV) of 65 – from the company’s Bayston Hill Quarry in Shropshire, which had also supplied the same stone used at Silverstone, Bahrain and Abu Dhabi Grand Prix circuits.
A special mix design ensured the asphalt remained malleable while being transferred through the tunnel to the paver to ensure the best possible surface finish.
Doody added: “Achieving the specific tolerances required continuous paving along the full length of the tunnel, so we had to guarantee a continuous supply of asphalt to the paver from Tarmac plants at Mountsorrel, in Leicestershire, and the Elstow plant, near Bedford.
“In two shifts, the paving teams worked from 7am to 7pm, laying 1,340t of asphalt with a seamless changeover without stopping the paver.”
ARP director Robert Lewis added: “We have worked closely with Stepnell, who led a professional team of great subcontractors, to successfully complete the civil engineering and building works. The team converted the tunnel from a wet hole in the ground to a pristine running surface that allows sophisticated vehicle testing.
“The tunnel can accommodate any size of vehicle from road and race cars to HGVs, although the latter could – obviously – not be turned around in the tunnel so would have to reverse out. Our specialist vehicle turn-table can turn around anything up to a long-base transit van.”
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