Teignmouth&Shaldon Museum

The year 2004 marked the 160th Anniversary of the passing of the South Devon Railway Act which brought, arguably, the country’s most unique and interesting railway to the town of Teignmouth, under the guiding hand of one of the most famous engineers of all time Isambard Kingdom Brunel.

The South Devon Railway was promoted as part of a trunk route from London to
Penzance, which started with the Great Western Company from Paddington to
Temple Meads in Bristol, continuing as the Bristol and Exeter Company between the
two cities, and as the South Devon from Exeter to Plymouth. Beyond Plymouth
the Cornwall Railway would carry the line across the Tamar and on to Penzance.

The entire system was built to the broad gauge of 7’0 1⁄4” between the rails, rather than the standard of 4’8 1⁄2”, which was adopted by most of the other lines of the day. Although the wider gauge was superior in engineering terms, it made physical interchange of traffic impossible and incurred, as a result, expensive trans-shipment costs wherever the two systems met. The broad gauge was abandoned in 1892 and the lines converted to standard width.

It has often been said that the curve where the line sweeps round East Cliff at Teignmouth and almost to the sea is the most photographed piece of railway in the world. Whether that is true or not it is certainly one of the most picturesque and, with the long sea wall and series of tunnels from the Teign to the Exe, a wonderfully bold piece of civil engineering worthy of its creator.

	In addition to its dramatic route along the coast, the South Devon Railway also achieved fame and a niche in engineering history in being the longest line to use atmospheric traction, whereby the atmospheric pressure of the air was used to propel the trains in place of locomotives. Sadly the system turned out to be a terrible and expensive failure.

In the atmospheric system a line of iron pipes, 15 inches in diameter, was laid between the running rails and a partial vacuum created within the pipe by means of stationary steam pumping engines, housed in handsome stone buildings, at intervals approximately every four miles along the line. Motion was imparted to the train by means of a piston which travelled within the pipe and which was sucked along or, in other words, pushed by the pressure of the atmosphere acting on the rear face of the piston.

Connection between the train and the piston was achieved by means of a narrow iron plate, which passed upwards through a slot in the crown of the pipe to the underside of the leading or piston carriage of the train. The slot in the top of the pipe was closed by a continuous leather flap valve which rendered the pipe airtight and maintained the vacuum in advance of the train.

The flap valve was made up of thousands of short lengths of stout leather, reinforced with iron plates and so designed that it would hinge upwards sufficiently to allow the plate connecting the piston to the train to pass along and then drop back and reseal the pipe after the train had gone by.

In theory the idea looked sound and Brunel had in fact been convinced by its practicability, not only by the knowledge that it had been adopted by two other, albeit relatively minor, railways but he had also personally witnessed demonstrations by its inventors, Messrs Clog & Samuda on the West London Railway in 1841.

It was also reasoned that money would be saved by not having to provide locomotives, that construction costs would be less, as a single line of rails would be laid, and earthworks would be reduced in the difficult and hilly country between Newton Abbot and Plymouth, as atmospheric traction could cope more easily with severe gradients.

Pumping stations were sited at:

Exeter (St. Davids), Countess Wear, Turf, Starcross, Dawlish, Teignmouth, Summerhouse (Bishopsteignton) and Newton Abbot.

In the event, however, numerous problems soon made themselves apparent, not only in the operating of such a novel system, but in dealing with the mechanical defects and breakages of all sorts, most of which were unforeseen. The leather valve gave trouble virtually from the start as it was liable to freeze, tear and not reseal properly with the result that it leaked and reduced the vacuum, causing the pumping engines to work harder and use more fuel than was allowed for in the original calculations. Water also collected in the pipe and the pistons were liable to be damaged entering and leaving the pipes. Starting and stopping trains at stations was both complicated and inflexible, reversing was impossible and shunting had to be done by men, horses or rival locomotives.

Despite all these difficulties, however, atmospheric trains started running between Exeter and Teignmouth in September 1847 with the service extended to Newton Abbot in the December of that year, the latter being the farthest point reached, although pipes and pumping stations were provided as far as Totnes.

It would seem that, by all accounts, the atmospheric railway staff were keen to make a success of the system, but the odds were hopelessly against them particularly as the pipe valves deteriorated and became more and more difficult to maintain and keep airtight.

The continuing financial loss to the South Devon Railway, resulting from what, for many decades, was referred to by the locals as the Atmospheric Caper, was put at about £400,000 or, say something like £40 million in today’s currency. Brunel survived the terrible blow to his judgement and reputation and continued to be employed by the Company as their engineer.

A section of the original cast-iron vacuum pipe and a picture of a pumping station, together with an original copy of the South Devon Railway Act, is on view at the Museum. Few other relics of the system survive, but the pumping station building at Starcross remains almost intact to this day.

For more detailed information:

Monograph No 2 - The Railway in Teignmouth & Monograph No 19 - Brunels Teignmouth
is available at £2-50 per copy (inclusive of Postage and Packaging).
Please do not send cash. Make cheques and money orders payable to ‘Teign Heritage’.
All enquiries and orders for this Monograph by mail only. Please ensure that your name and full postal address are included with all correspondence.