Victorian Train Tunnel Turned Test Track

Characterizing the aerodynamic performance of a vehicle usually requires a wind tunnel since it’s difficult to control all variables when actually driving. Unless you had some kind of perfectly straight, environmentally controlled, and precision-graded section of road, anyway. Turns out the Catesby Tunnel in the UK meets those requirements exactly, and [Tom Scott] recently got to take a tour of it.

The 2.7 kilometer (1.7 mile) long tunnel was constructed as a railway tunnel between 1895 and 1897, thanks to the estate owner objecting to the idea of “unsightly trains” crossing his property. The tunnel’s construction was precise even by modern standards, deviating only 3 mm from being perfectly straight along its entire length. It lay abandoned for many years until it was paved and converted into a test facility, opening in 2021.

To measure the speed without the luxury of GPS reception, a high-speed camera mounted inside a vehicle detects reflective tags mounted every 5 m along the tunnel’s wall. This provides accurate speed measurement down to 0.001 km/h. A pair of turntables are installed at the ends of the tunnel to avoid an Austin Powers multi-point turn (apparently that’s the technical term) when turning around inside the confined space.

Due to the overhead soil and sealed ends, the temperature in the tunnel only varies by 1 – 2 °C year round. This controlled environment makes the tunnel perfect for coastdown tests, where a vehicle accelerates to a designated speed and then is put into neutral and allowed to coast. By measuring the loss of speed across multiple runs, it’s possible to calculate the aerodynamic drag and friction on the wheels. Thanks to the repeatable nature of the tests, it was even possible to calculate the aerodynamic losses caused by [Tom]’s cameras mounted to the outside of the vehicle.

The Catesby Tunnel is an excellent example of repurposing old infrastructure for modern use. Some other examples we’ve seen include using coal mines and gold mines for geothermal energy.

28 thoughts on “Victorian Train Tunnel Turned Test Track

    1. It used to be, at least. Over here in Germany, the experimental Transrapid was being developed once, raising similar hopes for a comfortable travel.
      It was floating very elegant on a magnetic field rather than scratching over metal.
      Sadly, the concept wasn’t as much valued as it should have been.
      A tragic accident on the proving ground caused by inattention then put an end to the project.
      It wasn’t the fault of the technology, though. In Shanghai, it was/is in daily use.

      1. The reason for the Transrapid being shelved was not so much the accident on the test track but rather the cost of the system per person kilometer. It was simply way too expensive for its passenger capacity, compared to any other rail transport system. That cost was almost exclusively dictated by the tons of copper coils in each kilometer of its electromagnetic rail, since the propulsion and levitation force was generated by the rail rather than the cars.

        1. Thanks for educating, Peter. Personally, I think that the officialstory was propaganda, in parts at least.
          But at its core, there’s some truth within – political interests were at play. The Transrapid wasn’t being wanted, an excuse for its termination was a welcome.

          Personally, I’m afraid it was because the DB was unwilling to invest in higher-end transportation, no matter how much it would have improved customer satisfaction. It’s not about speed alone, which is often being forgotten.

          Our Telekom is/was no different, I think. Remember the years in which it refused to invest in DSL and Vectoring, rather doing proper fibre glass? To the home, I mean. The “last mile” argument is/was a joke. Bandwith is/was always lost without fibre, because the whole neighborhood shares a single DSL hub.

          Anyway. We Germans see always costs, rarely the chances. We don’t understand the difference between an investment and a financial loss. That’s why we never lead in anything anymore. We do have good engineers that learn here, then leave Germany ASAP.
          At this point in time, no one could say whether the Transrapid was successful or not. Maybe customers/travelers woukd have loved it so much that they would have paid for expensive tickets. But the main problem is, that the Transrapid was barely given a chance. In Germany, I mean. It is successful in Shanghai, for +20 years.

    2. > Public transport is the future.

      Only if we find ways to stop people from infecting each other with their germs, in those moving metal tubes packed with people.

      When I went to my work with public transport, I used to get the Flu or something else that would make me stay home with a fever, almost twice a year on average.

      For the past 8 years I have been driving by car and motorbike to my work, and have only been sick once or twice in all those years.

      I wonder how many days or maybe even years it has added to my lifespan.

      1. I’m also fearing for the time that we will have megacities, like in I, Robot (I’m talking about the book here). Imagine an outbreak of some sickness, how fast it would spread with so many people in such a small place. For sure, such a city can only be managed by a government like the Chinese government. They will just isolate whole sections of the city for months, to contain the outbreak. COVID19-isolation to the power of 2. Self-isolation will not be an option anymore.

          1. Exactly this. Not to mention once they’re at work or at the store, guess what, they’re surrounded by public transport users. What a naive take (I must have private transport and also use that as a reason against public transport).

          2. The American South? Maybe at gunpoint.

            I mean, I’d encourage it. Put a stop to that nonsense demand to recklessly endanger others, the same way we would if they were emptying a gun into the air over a suburb.

      2. When air travel started up someone wrote that it would be the best/worst way to spread a plague around the world. I have hunted for it but can’t find out who said that. However, we recently experience it.

        1. Those people were exposed just not contagious during flight. They became sick when they arrived at their destination.

          I got my shots, traveled, and only got sick at home shopping in a grocery store

          1. Citation needed.
            The odds that no one is infected during all the multi-hour flights around the world… vanishingly slim.
            Even your anecdote doesn’t provide any support for your curious assertion, you could easily have been infected on your plane journey.

      3. I have never been as non sick as when I was a taxi driver. Others got sick left and right, i did not.
        The immune system gets stronger with exercise.
        But public transport always seem to suffer from one of two causes, either not enough passengers so tickets are very expensive/lines get cut, or too many passengers so tickets get expensive.
        By some crazy mechanism it always seems to be cheaper to fly than to go by train?
        Someone is bad at planning.

    3. It’s a nice idea, but very few public transport systems actually generate enough revenue to be self sustaining and instead need substantial subsidies to stay in operation. Hardly the future.

      1. The roadway system that private cars drive on isn’t generating enough revenue to be self sustaining and needs substantial subsidies to stay in operation. Same with sidewalks and parking lots.

        1. The revenue need not be direct. Schools don’t generate revenue either, yet taxpayers pay for them.

          Reduced energy costs are a good thing for a society. As is an educated populace.

    4. For a bit of context the railway line in question is the Great Central Railway. It was the last major mainline built in the Victorian era. It ran from London to Manchester via the English Midlands and South Yorkshire. It was built to be faster than the existing West Coast Mainline and the Midland Mainline. As a bonus the stations in Leicester, Loughborough and Nottingham were way better located in the respective cities.

      Sadly in the obsessive drive to remove duplication of routes the WCML and MML survived the 1960s (Beeching) cuts. Probably the worst decision in UK rail history.

      The situation has turned full circle. HS2 a new high speed line is being built between London and Manchester via the west Midlands to mitigate crippling congestion. And much in tunnel, to appease land owners.
      All at the bargain basement price of £100bn and rising.

        1. I make that journey quite frequently between Sheffield and Manchester. The last time only last week for a walk in the peak district. It is a very scenic route.

  1. What isn’t mentioned explicitly in the video is _why_ manufacturers require coast-down data. The reason is that the results are used to calibrate the friction models for the dynamometer rollers used in the emissions test.
    Without accurate rolling resistance on the dyno at the test speeds the emissions test data would be worthless.

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