Is it possible to convert a BLI Q2 into a Q1? Thank you.
The Q2 has almost nothing in common with the Q1 except Pennsylvania ownership and duplex drive.
Ed might be able to supply you with elevation drawings of the Q1 and Q2 that will show in detail how different they are.
According to records at the Hagley Museum, the Q1 was designed as the ‘follow-on’ to the M1/Mia – think of it as a 5/4 scaleup – with all the changes deemed necessary for higher-speed service. The implications of modern balancing methods hadn’t quite set in, so the relatively tall 77" drivers, on a duplex engine already minimizing augment, made the engine less than a full ‘dual-service’ design: it was optimized for long M&E trains, not PRR 50mph freight. You do not want to model the rear ‘engine’ of the Q1 with its convoluted external steam piping and backpedaling cylinders rigger around the firebox throat.
The Q2 was fully successful in its ‘intended’ role: power to supply priority-speed 150-car trains to support Operation Downfall. When that turned out to be unnecessary, the operating differences between the big duplexes and the (finally debugged!) J1 and J1a were too slight to justify All That Additional Maintenance for four cylinders, their valve gear, and the wrong implememtation of the very sophisticated (for the Forties) antislip arrangement. On top of that you had bioler-steel follies, and the general end of innovation in modern steam between 1947 and 1950.
1 Like
Q1
http://prr.railfan.net/diagrams/PRRdiagrams.html?diag=Q1.gif&sel=ste&sz=sm&fr=
Q2
http://prr.railfan.net/diagrams/PRRdiagrams.html?diag=q2.gif&sel=ste&sz=sm&fr=
Cheers, the Bear. 
1 Like
The early streamlined version of the PRR Q-1 is attractive. The diameter of the driving wheels is 77 in., which is larger than the 69 in. of the Q-2, so even if you use them, it will not be an accurate scale. On the other hand, brass models have been released in the past, so it would be more realistic to wait for them to appear on the used market. In HO scale, there were NJICB/Dai-Young (1978) and Key Imports/Samhongsa (1998).
3 Likes