Built between 1942-1946, 52 of these engines were made for express passenger work. They were 'duplex' engines, having two sets of drive wheels on one frame. These were incredibly powerful engines, to the point PRR crews would overdo the throttle, leading to severe wheel slip problems. This is an exclusive problem to the PRR, as other railroads that trialed them had less issues with them. When they were properly running, they were hugely fast, rumored to reach speeds of 140 mph in service. All were scrapped in the 1950s, though a new-build is being construed to break the current steam speed record of 126. These honestly are super cool, and have a very intimidating look, and it's a shame none made it to preservation
