Pfalzbahn / Bavaria 2-6-4 Locomotives in Germany

Class Pt 3/6 // BR 77.1 (Locobase 5755)

Data from Christian Lindecke's website [] (visited 28 Nov 2003). Additional data from US Military Railway Service Equipment Data Book -- German Locomotives supplied by Allen Stanley from his extensive Rail Data Exchange in March 2004. Supplemented by [], last accessed 14 May 2011, last accessed 14 May 2011 and from cnum_8XAE739, Exposition universelle, Groupe VII. Classes 39 et 40: Industrie des Transports-Chemins de fer et Tramways. Exposition internationale des industries et du travail de Turin 1911 (Paris: Comite Francais des Expositions a l'Etranger, 1911), p. 18.

These 90-km/h (55 mph) engines were the superheated version of the 1908 P5s. Taking advantage of the greater efficiency of the superheater, the design had a lower boiler pressure (13 bar vs 14 bar). Fire-side tube diameter was 40 mm and the flues measured 124 mm internally. Those measurements a combined tube-and-flue heating surface area of 100.62 sq m (1,083 sq ft); Locobase shows the water-side diameters and areas. The design's trailing load on a 2% grade rose from 140 tons to180 tons.

They were built in two batches. The first nine were delivered to the Pfalzbahn in 1911-1913; see Locobase 5754. The last ten came to the Bavarian in 1923 as Pt3/6.16 class; these operated expresses between Garmisch and Partenkirchen to Munich.

Very quickly all were taken into the newly formed DRG as the BR 77.10 class. Those that were still fitted with the unsatisfactory Pielock superheater (see Locobase 13565 for a detailed description of this unit) were retrofitted with the Schmidt version in 1925. An impressive number of these Munich-based tanks served through World War II, being retired in 1950.