Monday essay: could the Great Central be used for HS2?

Construction of HS2 is going ahead, after the Government authorised the issuing of Notices to Proceed to the main contractors for Phase 1 between London and Birmingham. But alternatives to the route, or details of it, are still being urged by some transport campaigners. Sim Harris considers the possibilities offered by the trackbed of the former Great Central Railway.

ONE frequently heard story about alternatives for HS2 concerns the Great Central Railway, the brainchild of Sir Edward Watkin (1819-1901). The GCR (‘the London Extension’ of the Manchester, Sheffield and Lincolnshire Railway) was opened on 9 March 1899, but Sir Edward had even greater ambitions. He had wanted to extend his railway across the English Channel.

The first test shafts for a Channel Tunnel were unsuccessful, but digging restarted in 1880 and some work was also done on the French side. By late 1882 the English trial bore from Dover was almost 2km long.

Widespread objections to what was seen as a threat to national security (even Queen Victoria is said to have been doubtful) ensured failure. After years of debate and mounting official concern about the possibilities of invasion the scheme was finally killed in 1898, when the High Court ordered the South Eastern Railway and the associated Channel Tunnel Company to stop boring beneath the sea bed.

It is frequently alleged that the Great Central Railway was built to ‘continental loading gauge’ so that international trains coming through the Channel Tunnel would have been able to use Watkin’s new main line, and this claim is also used to bolster a further myth that a reopened Great Central would be a workable (and cheaper) substitute for HS2. Although the GCR was well-engineered, neither of these claims bear close examination.

There was no such thing as an agreed ‘continental’ gauge until 1912, when a convention held in Bern confirmed some specifications. This agreement gave birth to the ‘Bern(e) Gauge’ in 1914, which is now a series of UIC standards. But there is no shortage of books and internet documents (including research for a master’s degree) maintaining that structures on the GCR were built to the ‘Berne gauge’. As the Bern agreement was only signed 13 years after the GCR had opened, this would have been a remarkable example of foresight.

Unfortunately for the Great Central/Channel Tunnel enthusiasts, Channel Tunnel trains would also have needed to be routed via the South Eastern Railway where the structure gauge was on the miserly side, even by British standards.

In any case, the GCR’s dimensions were smaller than those of the future Berne Gauge. The Berne loading gauge width is usually accepted to be 3.15m, while the Great Central was built to a width of 2.82m. The Berne Gauge maximum height was 4.28m, while the GCR equivalent was 4.09m.

In other words, there was nothing very exceptional about the dimensions of the GCR. Although its dimensions were comparatively generous when compared with some of the older British railways, this was probably to comply with revised Board of Trade regulations, and most trains from continental countries would still have been too large for the line. One account of the Great Central suggests that two bridges were built to ‘unusual dimensions’ to allow for future widening if Channel Tunnel trains ever arrived. This would have been an early example of what is now known as ‘passive provision’, but it was never needed.

In any case, by the time the Great Central was opened Watkin’s Channel Tunnel dream was dead. Trains from continental Europe would never run along the main line from Marylebone to the Midlands.

As for using the trackbed of the Great Central for HS2 now, this would be a very poor second best. HS2 is to be built to a true international structure gauge, known as UIC ‘GC’. This allows a rolling stock height of 4.70m, compared with the usual British maximum of 3.91m. UIC GC trains are also wider, at 3.29m (the British equivalent is 2.82m). The platform profiles are different as well.

The Great Central falls well short of the requirements of UIC GC. The surviving bridges and tunnels would have to be expensively enlarged, while a further height allowance would be needed for the OHLE. Some structures have been demolished and would have to be replaced. Even the width of the formation (where it still exists) would not be anything like enough, because High Speed lines typically measure five metres between the centres of parallel tracks, while the distance between the fences on each side can be as much as 22m.

Neither do the fans of the Great Central explain what would be done in towns like Brackley and Rugby, where the formation has disappeared entirely under later urban development. New avoiding lines – completely new stretches – would presumably be needed.

Sir Edward Watkin can hardly be blamed for not planning a Victorian steam railway with a likely maximum speed of 75-80mph (120-128km/h) to the dimensions of HS1 or HS2, but the Great Central was not the equivalent – in any way – of a modern High Speed line.

This is a revised and updated version of analysis first published in the March print edition of Railnews, RN277. Copies of the current or recent editions can be obtained by calling 01438 281200 from UK numbers or +44 (0)1438 281200 internationally, and selecting Option 2.

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