Tuesday, September 6, 2011

"Houston, We have a problem"

We had family visiting for most of the weekend, so I didn't get a lot done on layout - until they left for the airport on Monday morning. I spent the first part of Monday afternoon getting the remaining feeders connected to the buss wires. Then I tweaked a troublesome turnout on the south end of Richmond (just beyond the bridge scene). Once I got the passenger cars through it without any issues I dug out the Division Point 2-10-4s and one of my Overland 4-8-2s. 


The 2-10-4 made it through the mainline route of the switch - the diverging route traveling northbound direction was no joy - that wasn't a surprise and is something I can handle with a timetable special instruction (there's no reason for a 2-10-4 to be on that siding anyway). 


Then I got out the first 4-8-2 - it ran back and forth just fine, I was thrilled. Then, the engine stopped. I mean it just froze. I immediately suspected a wiring issue - after all I was testing the wiring. Then I figured perhaps it was a track issue - no problem, the engine was on the rails. Then I noticed the side rods were a funny shape - the main rod looked like a mountain range - going up and down. That can't be right. Apparently the long screw holding the valve gear assembly into the third driver had loosened to the point where it slipped out of the driver on one side - throwing everything out of whack.



I put the engine back in the box, and put the other 4-8-2 on the track - checking it to be sure it was in good shape. It ran back and forth even better until it started stuttering - I shut it off right away and examined it closely. Believe it or not, this engine had the EXACT SAME issue - loosing it's siderod screw after a few runs back and forth. 
So now I have two engines that are down hard until I have enough time to really work through the issue. I've never been much of a locomotive mechanic - looks like that's about to change. 
I'm so mad I could spit.

3 comments:

  1. Marty, about 40 years ago I had the same problem with a Santa Fe Northern by PFM. After much time and really hokey fix with an extra long screw, I realized that the problem was that the shoulder of the main driver screw was too short. If the screw was tightened down all the way the side rods bound; and if it was loosened enough for the engine to run the screw was not really seated: and it would unscrew in a few laps. I think that your main rod may have a side rod screw instead of the correct length for the main rod. If so, the fix is to get the right length and all will work . Maynard Stowe

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  2. One fault could be considered an honest mistake. two identical is a design/build flaw. Let us know the solution when you discover it, Marty!

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  3. A little bit of an update. These engines include a Bopox style driver as a replacement for the spoked wheel - in both cases the former owners replaced the original driver with the Bopox wheel and then re-installed the eccentric backwards . . . so the motion of the rods actually backed the screw out of the hole.
    Not sure if this is really what happened, but a couple of guys on my Yahoo Group saw the picture and noted they'd had the same issue with these engines. Other projects have taken priority, but I do need to get this fixed!

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