While the overall design reduced drag compared to the PRR's existing J1 class, the streamlining was ultimately removed around 1944, due to the minimal benefits at low freight speeds, and increased maintenance costs.

PRR's Board approved $595,000 for the construction of this experimental Class dual service locomotive on Oct. 9, 1940. it was built in March 1942.

[3] As a locomotive designed for dual service like PRR M1s,[4] it was given larger-sized driving wheels at 77 in (1.956 m), which was as large as the Grand Trunk Western class U-4-b 4-8-4 "Northern" type.

The Q1's streamlining was in the form of a bluntly-pointed nosecone on the smokebox front as well as extended side skirts covering up the locomotive's pipework.

Jones, Chief of Motive Power, told Altoona that the Q1, #6130, would be considered a passenger engine as far as striping and lettering were concerned.

[7] Its first revenue run occurred on May 31, 1942, from East Altoona to Enola with 125 cars and 10,000 tons; 40 mph (64 km/h) was made on a level track at 40% cutoff.

In December 1944, it appeared at a PRR exhibition in Chicago Union Station entitled "Presenting a Line of Modern Coal-Burning Steam Locomotives".

This had smaller drivers, cylinders mounted in front of the driving wheels, was built largely unstreamlined and designed for freight service only.