Tuesday 25 May 2010

ELL week: from ripples to rails

Much of the East London Line between New Cross Gate and Croydon follows the route of the old Croydon Canal. Before the railway craze, there was something of a canal craze and a network of inland waterways was dug out of the countryside so that goods could be moved by barge.

However, many canals suffered badly when the railways started to compete: here was an even quicker method of transporting cargoes. The Croydon Canal was no exception, and indeed fared worse than most as a flight of locks at the northern end made it particularly slow and narrow. The railway came, and didn't merely render it redundant but largely physically destroyed it. (Diamond Geezer has looked at what's left.) They did so not as some act of revenge but because they wanted to use the same route for their trains; after all, what could be more convenient?

Not that it was as simple as replacing water with steel. The railway company had to straighten bits out and dig cuttings, all under engineer William Cubitt who also worked on Crystal Palace and invented the prison treadmill. Like so many major projects, it went over budget; the London and Croydon Railway's financial performance remained poor until it merged with a number of other companies to form the London, Brighton & South Coast Railway in 1846.

There is one episode in the company's history, though, which is quite unusual: in 1844 it found the money for an intriguing experiment. With Parliament's permission, it laid a length of track between Croydon and Forest Hill to test an atmospheric railway system. This worked by having two pumping stations, joined by a pipe which ran between the rails. Inside the pipe was a piston. The pumping created a vacuum ahead of the piston, while air was let in behind. The resulting atmospheric pressure pushed the piston through the tube. That piston was in turn joined to the train above via a slit in the pipe sealed by a leather valve. (Read a contemporary account of the railway on IanVisits.) Unfortunately, the pumping engines had lots of problems, while keeping the pipe airtight was even more difficult. The railway would never be converted to the atmospheric system; the half-a-million-pound project was a failure.

What if it had worked? The Victorian passengers on this line would have been able to travel in trains immeasurably more quiet and clean than those pulled by steam engines. Indeed, their experience might have been closer to that of passengers on the East London Line today!

Image: the Croydon pumping station, 1845, from Wikipedia Commons.

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