I just have some hearsay, that it was considered a bad engine.It was the first of 10 decidedly home-made engines, and it had its bugs. I understand it derailed more than other engines in its class. Usually when an engine was running out of flue time the Grande relegated it to the Farmington Branch. The 490 ran down there a LOT in the late 1950s and early 1960s. Broken axles happend with various engines, but was not an ongoing problem. 490s did have a problem with the frames cracking right over the trailer truck. Some wags think the 490s might have made better 2-8-4s!