Sunset/3rd Rail Santa Fe 2-10-2 3800 class

Only when it’s running? …..are you sure it’s not electrical noise? …..what happens when you try & roll the tender on the track by itself?…..we’re gonna need a few more clues …..I’d think….flip the tender over, & take a picture too,….let’s see what you’re working with…..I had a 3rd Rail that squalled the devil, and it was the draw bar rubbing the first axle of the front truck, ….

Pat

Thanks for your comments, harmonyards. I checked the axles for tram, and all are good -- I thought maybe one axle was out of parallel and was dragging along at an angle. And the engine runs very quietly on its own. I coupled the tender to the end of a train and ran it around the track, with the same scratching noise -- not terribly loud but noticeable and annoying -- so it can't be interference from the drawbar. I've never run across a situation like this that wasn't easily remedied by a couple of drops of oil in a journal, but in this case the axles have all been lubricated and the noise persists.

perhaps a wheelset is rubbing on the underside of the tender deck. which is only evident when trailing weight causes a truck to cant under load. which may appear to be a loose truck to body bolster connection.

the description of the sound does to me sound like a flange rubbing on the underside of the frame or some detail.   It is something to look into I think.

Does it make the sound on straight track?  On a curve to the left?  On a curve to the right?

If the sound goes away in a certain situation, that can be a clue on where to look.

My money is on a worn axle bearing allowing the wheelset to slide over and hit the truck frame.

I have a 2 rail version of this engine and it had an intermittent squeak coming from the tender that went away with oiling.

I figured put the problem and fixed it. The axles are shouldered (smaller diameter inside the journal) and the shoulder was intermittently rubbing against the side of the journal, which has a slightly raised annular ring on the inside edge, causing a squeak.

There was quite a lot of side play in the axles, so I was able to fit a M 2.5 washer to each end of each axle, and the problem went away.  Mine is the 2-rail version of this engine, also.

Yay! Glad you were able to figure it out and fix it. Now you can enjoy it over Christmas...

Mark in Oregon

@B Smith posted:

I figured put the problem and fixed it. The axles are shouldered (smaller diameter inside the journal) and the shoulder was intermittently rubbing against the side of the journal, which has a slightly raised annular ring on the inside edge, causing a squeak.

There was quite a lot of side play in the axles, so I was able to fit a M 2.5 washer to each end of each axle, and the problem went away.  Mine is the 2-rail version of this engine, also.

There wasn’t a brass bearing in the journal to oil?

Yes, the side frames are brass and the sprung journal boxes are drilled to accept the axles. The problem was that the axles are "shouldered," meaning the part of the axle that fits into the journal has been turned down to a smaller diameter than the rest of the axle that the wheels are pressed onto. That left a "shoulder" where the diameter of the axle changed, and this "edge" was rubbing against the side of the journal box, which was not smooth or polished. A small stainless steel washer on each end of the axles took up some of the side-to-side play and gave the "shoulder" something smooth to run against. Oil by itself did not take care of the original problem, which is what puzzled me and led to this fix.

To be fair -- An alternative or contributory source of the squeaking could be that one or more of the axle ends was bottoming out in a journal (i.e. hole not drilled deep enough) and that adding washers prevented the end of the axle from hitting the bottom of the hole in the journal (which could have caused the noise). Whatever the precise cause or causes of the squeaking, adding washers fixed it!

Cool. I understand now.