The locomotives of the Est with the numbers 3501 to 3890 are considered the most important French 4-6-0 passenger locomotives. They were sorted into power class 11 by the Est. These 390 locomotives were developed from the series numbered 3401 to 3500 and built between 1901 and 1912 by a large number of companies from France and Germany. The first were the 3501 to 3520 from Maffei in Munich, followed by the 3521 to 3550 from Schneider et Cie. These were Du Busquet-De Glehn type locomotives, i.e. with a four-cylinder compound engine and drive on two axles. The locomotives up to number 3790 used saturated steam, from No. 3719 of 1911 superheaters were installed. The newer locomotives also had a larger diameter of the high-pressure cylinders with 370 instead of 350 mm and were classified as series 11s to distinguish them.

230 B 786 in 1958 in Chaumont/Marne

Ben Brooksbank

Although these locomotives with a driving wheel diameter of 1,750 mm were no express locomotives, they had a streamlined cab and were approved for speeds of 110 km/h. They were stationed at all depots in the Est network. After the locomotives had been delivered from the factory with superheaters and larger cylinders from 1911, most of the existing locomotives were converted in the same way. These converted machines were listed as the “11s bis” series. 36 examples were modernized by André Chapelon in 1932. They received new exhaust systems with six nozzles and smoke deflectors, which improved their power somewhat. When the SNCF was founded in 1938, there were still 388 examples, which were now designated 1-230 B 501 to 890. The twelve engines that had not undergone any conversion were withdrawn from service in 1951. The last of the rest disappeared in 1967.