was used, with a single pumping station at Dalkey, at the upper end of the 2,400-yard run. The engine created 110 ihp and had a flywheel of 36 feet diameter. Five minutes before the scheduled departure of a train from Kingstown, the pumping engine started work, creating a 15-inch vacuum in two minutes. The train was pushed manually to the position where the piston entered the pipe, and the train was held on the brakes until it was ready to start. When that time came, the brakes were released and the train moved off. (The electric telegraph was later installed, obviating reliance on the timetable for engine operation.) On 17 August 1843, the tube was exhausted for the first time, and the following day a trial run was made. On Saturday 19 August, the line was opened to the public. In service, a typical speed of 30 mph was attained; return to Kingstown was by gravitation down the gradient, and slower. By March 1844, 35 train movements operated daily, and 4,500 passengers a week travelled on the line, mostly simply for the novelty. It is recorded that a young man called Frank Elrington was on one occasion on the piston carriage, which was not attached to the train. On releasing the brake, the light vehicle shot off at high speed, covering the distance in 75 seconds, averaging 65 mph. As this was the first commercially operating atmospheric railway, it attracted the attention of many eminent engineers of the day, including Isambard Kingdom Brunel, Robert Stephenson, and Sir William Cubitt. The line continued to operate successfully for ten years, outliving the atmospheric system on British lines, although the Paris – Saint Germain line continued until 1860. When the system was abolished in 1855, a 2-2-2 steam locomotive called Princess was employed, incidentally the first steam engine to be manufactured in Ireland. Although a puny mechanism, the steam engine successfully worked the steeply graded line for some years. Paris – Saint Germain In 1835, the brothers Pereire obtained a concession from the Compagnie du Chemin de fer de Paris à Saint-Germain. They opened their 19 km line in 1837, but only as far as Le Pecq, a river quay on the left bank of the Seine, as a daunting incline would have been necessary to reach Saint-Germain-en-Laye, and locomotives of the day were considered incapable of climbing the necessary gradient, adhesion being