VGF’s underground trains

Like the trams, Frankfurt’s underground trains are identified by a series of letters. To differentiate them clearly from the various types of tram, the types are designated with a “U” for “Underground” in front and then an ascending sequence of numbers. The types in service on the VGF underground route network are the U2, U3 and U4. These should not be confused with the designations of the underground routes (U1 to U7). For instance trains of the U3 type run on Route U4.

One particular feature can be seen in the Type P. It was originally used as a tram, but they can now be found in a converted form on the underground routes. To differentiate between them an addition is made to their type designations:

1st version: P-units – vehicles with full folding doors (no longer in service)
2nd version: Pt-units – vehicles with divided folding doors and fold-out steps
3rd version: Ptb-units – similar to the 2nd version but with the door area widened for the underground area.

The underground trains run on routes with varying platform heights, with the result that not all vehicles can be used on every route.