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Not far from my friend’s house, a sign announces that you’re standing on Atmospheric Road. It is not, as you might think, a judgment on the beauty of the area, but rather a remnant of another of Ireland’s Strangest Railways.

In 1834, the very first passenger railway opened on the island of Ireland, from Dublin to the major port suburb of Kingstown.1 It prospered, and in 1840 the decision was made to extend the line another two miles to the village of Dalkey 2, along the line of the old horse-drawn Dalkey Quarry Tramway.3 But there was a problem – the route was steeply graded uphill to Dalkey and tightly curved, both problems for the primitive locomotives of the era. Then company treasurer4 James Pim heard of an experimental system built by Samuel Clegg and Jacob and Joseph Samuda, which was being tested at Wormwood Scrubs outside London and might be just the answer the Dublin & Kingstown was looking for. This revolutionary idea was the Atmospheric Railway.

So what is an Atmospheric Railway? To start with, locomotives are heavy. To haul trains they need fuel, and in 1840 the fuel was coal. Therefore, engine power is wasted moving both the locomotive itself and its fuel. On top of that, coal-fuelled locomotives produce smoke, soot and noise, and their weight causes wear and tear on the track. But what if you could supply the motive power remotely? What if you could generate power elsewhere and transmit it to the train? Nowadays, this is completely unremarkable – this is the basic principle of electric railways the world over. In 1840, they didn’t have electricity, but they did have air.

The vacuum keeps the leather flap sealed to the pipe until the train comes along.

The principle of the atmospheric railway is simple. A 15” pipe runs down the centre of the tracks. A slot along the top of the pipe is sealed with a continuous leather flap. A piston attached to the underside of a carriage sits in the pipe, and a pumping station at the end of the line forms a vacuum, “sucking” the train along the line. Therefore a pumping station could “suck” the train up the hill to Dalkey, and it could simply roll back down to Kingstown.

The D&KR petitioned for a government loan of £26,000 and construction began on the Dalkey Atmospheric Railway. Building was complicated by the fact that without an Act of Parliament, the railway could not cross public roads, so the line ran under ten bridges and short tunnel on its two-mile route.

A map of the south Dublin coastline.

On the 18th of August 1843, the very first public train ran on the Dalkey Atmospheric Railway. At the Kingstown end, the train was pushed by hand until the piston engaged with the tube. The pumping engine up at Dalkey evacuated the entire pipe in just two minutes, and the train was held by its brakes until loaded. The seven carriages could easily handle a load of about two hundred people, and with nothing but a slight hiss, the train shot up the hill to Dalkey at thirty miles per hour. The whole trip took about four minutes. From there, the train would freewheel back down the hill to Kingstown. The pneumatic pipe ended slightly short of Dalkey station and the train was carried the last stretch by momentum alone. If the brakeman applied the brakes too enthusiastically on either the up- or downhill run, it was possible for the train to stop short of either station, obliging the Third-class passengers to get out and push.

The line was a roaring success. In 1844, they were running 35 trains a day, one every half hour, and recorded 4,500 passengers a week, many travelling simply for the novelty. The early success of the line led to plans to extend to Bray, further down the coast, but these came to naught. The gloss started to wear off the Atmospheric Railway concept, especially after the financial failure of the South Devon Railway, a much larger implementation of the system by Isambard Kingdom Brunel. 5 Improvements in locomotive technology also led to engines that could handle the turns and climbs of the Dalkey line. When the D&KR joined a scheme to run trains from Dublin all the way to Wexford, the decision was made to convert the line to a standard railway. The last Atmospheric train ran on April 12 1854, and the line was rebuilt.

A well-known illustration of the train at the Kingstown end.

There are two particularly amusing incidents associated with the Dalkey Atmospheric Railway. The first is probably apocryphal – the leather flap that sealed the pipe was greased and sealed with tallow to keep it airtight, and a common urban legend is that the tallow attracted rats, who would chew the leather and occasionally be sucked into the pipe, propelling the poor rats at extreme speed into the pumping engine. The other is the story of a young man by the name of Frank Elrington, son of a Trinity College academic. He was sitting in the piston carriage, which was not attached to the rest of the train, when it was accidentally engaged with the pipe. The lightweight carriage shot up the hill to Dalkey at over 70mph, completing the journey in just over a minute and quite possibly making the hapless Elrington an early holder of a land speed record!

The modern DART line in the early 70s. That siding off to the right was a legacy of the old Atmospheric Railway route.

Today, very little remains of the Dalkey Atmospheric Railway. Part of the route at the Kingstown/Dún Laoghaire end is now the DART 6 line. You can still see the portal of the line’s tunnel, which has now not had a train through it since 1854. The old horse-drawn tramway line it followed was known as The Metals, and survives as a network of pleasant walking paths leading from the old quarry in the hill above Dalkey to the quay in Dún Laoghaire. I was hoping to go out and take some pictures myself last weekend, but work and weather ruined my plans. So it goes.

And that concludes the third and final part of my Strange Railways of Ireland series. (If you’re not sick of hearing about railway engineering yet, you can revisit parts One and Two here and here.)

Over to you! What have you been reading this week, and what have you been thinking about? I’m also going to add the sign-up sheet for further History Thread articles below. We already have a few contributors lined up and I would be excited to read more from all of you.