I can vouch for the fact that it is a wild ride in the cab of a 470 (K-28)when going fast....
One night, Engr Bill Holt and I took the 476 from Chama to Durango pulling empty passenger equipment that had gone east to Alamosa on a special railfan run. We had to get the coaches back to Durango in time for them to be inspected, and made ready for the second section Silverton train. An east end crew brought the train to Chama and Bill (Wild Bill) and I took them west.
It was after midnight when we pulled out of Chama, and dark, with a full moon peeking over the ridges to the south. Beautiful calm night.
Now old Bill liked to run fast...making "San Juan Time" he called it.
I had no idea! By the time we topped the hill at Amargo, he had her hooked up until the exhaust was a steady roar, and it was all I could do to brace my butt against the cab while I stomped the peddle and tried to hit the fire door. I managed pretty well, was able to keep her hot, and only showering old Bill with coal a time or two and he was grinning and having the time of his life....I was a little scared, hoping we wouldn't run over a cow or something we didn't see in the track.
He had been pretty well given verbal approval to
"make the time" and didn't (for once) have to worry about some trainmaster out along the line
or riding the caboose pulling him down for excessive speed. (That happened on another trip
at Allison, eastbound..Trainmaster H.V. Meek got on the caboose without us knowing it and he pulled the air on old Bill and ate his butt out for running 20 miles an hour! I had a hard time keeping a straight face while all that was goin on.)
Anyway, we got over the road OK that night. I had no idea one of those engines would go that fast (must have been all of 30-35 MPH, but it felt like 90!) We pulled into Durango a little after sunup, in plenty of time for the equipment
to make the second train. I had a sore butt for a week from the pounding I took bracing myself while firing. What a ride!