What decoder do you have in this engine?

I've had the issue of being stupid before.

🫨🫨😂😂

You do each driver set one at a time.  Articulated locomotives like the big boy are really two locomotives under one boiler.

Does this describe for you having issues with?

https://en.m.wikipedia.org/wiki/Crosshead

I think you're talking about what the Railroads in the past called the crosshead, which drove the main rod, and the crosshead guide, which is apparently the rail you were talking about.  I wish I could see a photo of it, but unfortunately, this otherwise excellent forum is not the easiest in the world to post photographs into, and I wish that our friend the Bach Man would remedy that.

Not exactly sure what the problem is, since I can't see a photo, but it sounds like the crosshead guide popped out of the cylinder block.  If it's that, you ought to be able to cement it right back in. But if it broke off, leaving a piece of it in a mounting hole, that's more difficult and for someone who sounds like they're not very experienced, it may be more trouble that it's worth.

You might have a display model on your hands. You would not be the only one to have such a model, spare parts are few and far between for old models in today's model railroad world.

These earlier Bachmann engines were not as well crafted as their models  today, and periodically people report problems with them.  I started buying Spectrum line Bachmann locomotives in 2007.  I'd have to count, but I probably have 25 of them now and I've never had any kind of real problem with any of them, just periodic maintenance stuff which is to be expected.

Did the cv reset work?

I concur.  Despite what lots of people say about a decoder just "plugging in," that's only with certain newer "DCC ready" engines that have the plug to do it. I highly suspect that your engine does not have it.  That means you have to back feed circuits to see what is what, then you have to install the speaker and solder it to the leads from the decoder, and possibly install a baffle.

There's this myth that persists that converting a DC locomotive DC and sound is incredibly easy, but it's only in "DCC ready" situations and you still have to solder the speaker in. 

At the point you appear to be in with Model Railroading,  I strongly urge you to find a tech to do this install for you.  Google is your friend, there are many out there.  It ain't cheap though. You may find that the cost of purchase and DCC installation may be almost equal to just buying a new locomotive with DCC and sound already installed.

Try a cv8=8 reset and see what that does. Remember to, after you send 8 to the CV, break the track power by rocking locomotive off of one rail briefly.  You should then see the headlight blink 16 times which means that the reset was successful.  The locomotive address will now be three and everything will be set at default.  Now, see if the engine runs with sound all the time. Then you can reset the address to whatever you want to be.

If you still get the same problem with the sound cutting out, then you probably fried the decoder.  But I don't think it's that bad, the DC surge probably just jolted some CV somewhere that needs to be reset.

Use wider radius than that if you at all can, such sharp curves like 15" are vexations to operation in many dimensions.

That's a pretty nice plan Jeffrey.  I'm very certain we're going to be moving in with one of the children and a couple years.

My present layout is very amenable to disassembly and reconstruction but it's a 50 foot point to point configuration. I won't have room for that wherever we go, I'll have to downsize my railroading and probably have to live with a 4 x 7 or 4 x 8 at max.  I'll be able to run my engines, but I'll also remember with great fondness being able to run local freight from point A to point B with two intermediate, passing tracks and set out points, like a real short line.

It's easy if you get a tech to do it.

The operative word here is "used."  Failure is probably the reason they were sold.  Buyer beware.

It's probably cheaper and easier to just buy a new one that is known to work and has a warranty.

BluNami does the same thing.

All good if you are digitally conversant.

I am not.

Call Soundtraxx.