The Bavarian engines with railway numbers 87 and 88 were superheatedsteam locomotives with the Localbahn AG (LAG). They were the last two engines that the LAG procured because shortly after their delivery in 1937, the company was finally nationalised. The locomotives were largely similar in their design to the TAG 7 locomotive, that had been developed in 1936 by Krauss-Maffei for the Tegernsee Railway AG (Tegernseebahn AG or TAG). TAG 7 (and its two sister engines) were the last branch line (Lokalbahn) locomotives to be designed and built in Bavaria. Unlike the two LAG engines, TAG 7 survived, first as the operating reserve for the Tegernseebahn and later as a museum locomotive. It is maintained by the Bavarian Localbahn Society and regularly used for museum trips around Munich.
TAG 7 and her sisters are the end of a line of development from the first six-wheeled, branch line engines at the end of the 19th century through the Bavarian GtL 4/4 (DRG classes 98.8-9 and 9.16) and the Bavarian GtL 4/5 (DRG Class 98.10 and 98.11). The relationship between the various types is externally very clearly visible. Under the old Bavarian classification scheme, the TAG/LAG engines would have been GtL 4/6 locomotives. Unlike the GtL 4/5, they took the original design of the GtL4/4 and extended it by two carrying axles that were each located in a Krauss-Helmholtz bogie. The coupled wheel diameter was increased from 1,006 to 1,100 mm. This resulted in very good riding qualities in both directions and the top speed could be raised to 70 km/h. The three locomotives were the largest and most powerful Lokalbahn locomotives ever to be operated in Germany.
Weisbrod, Manfred (1991). Dampflokomotiven deutscher Eisenbahnen, Von Privatbahnen zur DRG (EFA 1.5) (in German). Düsseldorf: Alba. pp. 128–130, 244. ISBN3-87094-139-1.
