The small tender locomotives of the class T 2I were procured by the Pfalzbahn specifically for use on pontoon bridges. What was special about these bridges was that the locomotives had to be as light as possible, but the sinking of the pontoons meant that an incline of around two percent had to be overcome continuously.
In order to meet these requirements, the machines were designed according to modern aspects. For example, an inside plate frame was installed, which offered high strength at low weight. In addition, the steam was extracted from the dome via a pipe, which led to the front of the boiler crown to the regulator.
The first series consisted of only two locomotives and was delivered in 1865. These operated the pontoon bridge over the Rhine near Maxau on the recently completed route from Winden to Karlsruhe. In contrast to the later variants, these had no driver's cab. These were reinforced with another three locomotives, which were added from 1869. Three more were procured for the bridge in Speyer within the same series. Two of the last three machines were later bought by the Baden State Railways and designated I b2. The latter ordered another machine, which was delivered in 1893.
Badische machine with a driver's cab later added
Die Lokomotive, June 1939
After the Pfalzbahn was taken over by the Bavarian State Railways, the machines were replaced by class D VI in the 1920s. Three still made it into the Reichsbahn's renumbering plan, but they were decommissioned shortly before the renumbering. Only the three units of the Baden State Railways survived until 1926. They were taken over by the Reichsbahn as road numbers 88 7501 to 88 7503.