2512 was a single de Glehn Compound 4-4-2 "Atlantic" type locomotive the railroad imported from France in 1904.

While the engine would be grouped with the class E locomotives as it was a 4-4-2 arrangement, it did not receive a formal classification, as it was a single experimental design.

The de Glehn was tested with seven other types of locomotive chosen to cover a variety in the essential principles of design.

[2] The performance of the de Glehn, as measured on the Test Plant, was used for comparison with later PRR locomotive classes such as the K29 and K2SA.

[3] The de Glehn was found to be too light for use by the PRR[4][page needed] and saw little service beyond their shops.