An Irishwoman's Diary

 

It was the end of an era. And it happened in the Co Dublin seaside village of Dalkey 150 years ago, in April 1854. For that was when the "atmospheric" railway line linking Dalkey and Kingstown (as Dún Laoghaire was called then) finally closed, writes Mary Mulvihill

If you've never heard of an atmospheric railway, don't worry; you're not alone: the idea had been consigned to the industrial dustbin long before the Dalkey line trundled to a standstill. But for a few years, atmospheric railways looked like they might be the future: a quiet, clean and lightweight way to travel, unlike those dirty, smoke-belching locomotive trains that some people were building.

The two competing approaches gave rise to what some called the "war of the propulsion systems", a war that marred the first 25 years of railway development. In one corner were George and Robert Stephenson, who pioneered the railway locomotive. They thought the way forward was to have a heavy steam engine pull carriages along a track.

Opposing them, in the atmospheric corner, was Isambard Kingdom Brunel, the noted English engineer. Brunel thought that attaching a heavy locomotive to a train was crazy: the engine would have to haul its own weight plus the weight of all the coal; you needed a substantial railway to bear the combined weight of train and engine; and the steam engine made for a noisy, smoky and rough ride.

It was surely faster, cheaper, safer and more comfortable, he argued, to put the steam engine beside the tracks and transmit the power it generated to the railway line; you could then run a lightweight, engine-less train of carriages on a correspondingly lightweight track.

Various engine-less systems were devised - some, such as "rack and pinion" trains and cable cars, are still used for short routes - but the main contender was Brunel's "atmospheric" or pneumatic railway, so called because the fixed steam engine generated suction power to move the train along the tracks.

Following successful experiments with small-scale models, the developers of the new Kingstown-Dalkey railway opted for Brunel's system, and in July 1844 they opened the world's first commercial atmospheric railway to considerable international attention. (A second atmospheric railway, the South Devon line, opened some months later on an experimental basis, was not fully operational until 1847, and closed a year later; a third, built in Paris, lasted for a number of years.)

A steam engine located in Dalkey generated the power to pull the trains uphill from Kingstown; for the return journey they simply fell slowly downhill under gravity - and if the momentum was not enough to carry the train into Kingstown station, third-class passengers were expected to get out and push.

The pneumatic system itself was intricate. First, a cast-iron pipe was laid between the railway tracks, and then an airtight piston in the pipe was connected to the train. The steam engine at Dalkey pumped air out of the pipe ahead of the train, creating a vacuum; and the atmospheric pressure of the air behind the piston pushed the train along.

The pipe had a narrow slot along its top through which the piston arm moved; a complex flap and valve system let the piston arm pass, but otherwise kept the slot closed; and wheels and rollers on the underside of the train manoeuvred the flap open as required, and pressed it back in place afterwards.

To ensure a tight seal the flap was also greased, but maintaining an airtight seal was difficult. The grease attracted rats which ate the leather; in summer, the grease melted away, and in winter the leather froze. Running the engine and pumping station intermittently was also costly.

Nevertheless, the Kingstown-Dalkey railway operated successfully for 10 years, following the old tramway cutting linking Dalkey quarry and Kingstown. Trains ran every half-hour between 8 a.m. and 6 p.m., averaging 30 miles an hour uphill to Dalkey, and 20 miles an hour when falling to Kingstown.

Amazingly, on one test run, the train actually broke the world speed record, averaging 84 miles an hour. Admittedly, only one carriage was used (all the others were uncoupled), but on that day the sole occupant, one Frank Ebrington, became the fastest man on Earth.