....Galloping 470's
Hi Mike:
I've got some great sound recordings of 478 back in the 70's doing the "478 Shuffle".
It was years later before I figured out why she did that and came up with the following theories:
1. the valve gear was slightly out of square.
2. there was a some lost motion (loose pins/bushings, link blocks, etc.
3. and most important... a creeping power reverse gear, with lost motion (worn parts in it).
The sound was most noticable when starting and the engineer was hooking her up looking for the "company notch" where she'd run decently square, but as far up the reverse quadrant as possible. As the reverse came back, all the slack was pulled out of the system. Then when within a few notces of center, he'd take a little more. The reverse would move back and keep going back taking the slack up in the motion and go further that the hogger wanted. With the worn and out of square valve gear, the gear would essentially center itself on one side, leaving only one half of the engine getting steam. To get her back pulling the engineer had to drop the reverse back down a ways to get her "hitting on all four corners" and try again hooking her up.
I have a great recording of 478 leaving Needleton showing this. 478 starts with a thunderous "1-2-3-4-1-2-3-4-1-2-3-4" exhaust. Then Larry Shawcroft grabs a bit too much on the reverse, the engine goes lame and he drops it down again.
The sound is "1-2-3-4-1--3--1--3--1-2-3-4-1-2-3-4".
The other thing it would do is creep up toward center when the throttle was eased off. Appearently keeping full steam pressure against the valves helped hold the reverse gear in place and when the pressure was reduced by closing the throttle back, the reverse would creep up. The same day I recorded 478 at Needleton, we pulled out of Elk Park about 15 minutes late. Larry fought the reverse and got 478 to run hooked up high on all 4 corners, at somewhere above 15 mph he eased off the throttle and 478 swallowed one exhaust, then 2 exhausts and eventually 3 exhausts. It was a rapid fire "1234,1234,123-,123-,1-3-,1-3-,1---,1---1234,1234....".
To hear the recordings all these year later after fighting uncooperative locomotives across the mountains, makes me laugh and show great pitty on Larry, Carl and Andy who fought with those nasty reverse gears all day long. I know after a day of torture with that thing I would have been ready to take the grate shaker bar to the reverse gear and make my own "fine adjustments".
As a post script I will add, that early in the D&S' history, Mark Yeamans tore apart 478's reverse gear and rebuilt it from the ground up. He lapped all the internal valves in, put new bushings in everything and tuned up up to perfection. He said it worked great for about 2 weeks then went back to it's old self again.
I bet everyone was glad to see the power reverse gear turned into flanger wing extenders.
