EST Class 13 (241 A) Steam Locomotive At the start of the Twenties, the French East Railroad (EST) urgently needed motive power unit to haul its heavy express trains on the line Paris – Belfort – Basle. The new locomotive was planned to haul a 700-ton train at a constant speed of 115 km/h / 72 mph on level track with a maximum speed of 120 km/h / 75 mph, which required a continuous performance of 2,720 horsepower. Even more ambitious was the requirement to pull 800 tons at 80 km/h / 50 mph on a 0.5% grade. Around 3,540 horsepower was necessary for this – an exorbitant level of performance for steam locomotives! A prototype delivered on January 17, 1926 by Fives-Lille with number 41.001 was the first time the "Mountain" 4-8-2 wheel arrangement was presented in Europe. In line with French practice, it was designed as a four-cylinder compound locomotive using de Glehn/du Bousquet principles with separately adjustable Heusinger valve gear for the high and low pressure running gear. After extensive testing, another 89 units were built between 1930 and 1934. They differed in several details from the prototype. Forty (40) units with road numbers 241 002-041 were delivered to the EST and 49 locomotives went to the ÉTAT. The prototype's road number was changed to 241 001. The class 241 A locomotives had a type of boiler new in Europe that was based on an American design with a large combustion chamber as well as Nicholson design thermal syphons. The boiler was fed water by means of an exhaust steam injector and two live steam injectors. The inner cylinders (low-pressure cylinders) worked on the offset driving wheel set and the external cylinders (high-pressure cylinders) worked on the second driving wheel set. A slide valve allowed high-pressure steam to reach the low-pressure cylinders during a start up or when greater performance was required. While the EST used their "Mountains" pulling heavy express trains on the routing Paris – Belfort – Mulhouse – Basle to bring vacationers bent on the mountains or starved for sun to Switzerland or to Italy, the ÉTAT ensured the connection to the ships landing at Cherbourg or Le Havre from the USA or Great Britain. Yet, the ÉTAT was not happy with their "Mountains", since the latter's' high weight and the large fixed wheelbase apparently caused a high degree of wear to the track. They therefore sold all 49 units to the EST. After its founding in 1938, the SNCF took over all 90 locomotives, which after different temporary numbering schemes were given the road numbers 241 A 1-41 (EST locomotives in the original sequence) and 241 A 42-90 (former ÉTAT units in an altered sequence). The SNCF used these locomotives until their retirement in the years 1960 to 1965 mainly between Paris and Strasbourg as well as Paris and Basle. Two examples remain preserved: road number 241 A 1 at the Mulhouse Railroad Museum and road number 241 A 65 in operational condition in Switzerland.