Re: Locomotives

Are the 490s really so troublesome as some make them sound? If so, why did they run them to the end of operations? I would have thought such a "troublesome" class would have been sidelined in favor of the '80s. Sure, side by side the 80's have some benefits of "newer technology" as far as the boiler is concerned, but is this really significant? I have never heard anyone say that the boilers on the '90s are in much worse shape than on the '80s. The main complaint seems to be concerning rigid staybolts and maybe the firebox design. The fact that they are "stiffer" than the 80's was a bother on the D&S, but these units saw daily service on Cumbres.
My question is are the K-37s getting a bum rap, or are they really that much more of a problem to operate/maintain than the good old '36s. Of course, then again, I've never had to replace a broken staybolt...........
Scott