In the model railroad Jurassic in a world of US made models, spare parts were always available from almost every manufacturer for almost every repair you could imagine.

That was then.  This is now.

Bachmann is better than almost everyone else at maintaining some semblance of parts availability, but with old models like the 4-8-4, the odds of finding there what you need are not very high.  You need to become accustomed to the present world of donor models, ie, finding ones to supply you with spare parts.  Often you can find them on online auctions with needs unrelated to your parts quest.  Or, You may find it easier just to buy used one that works well and keep the ones you presently have as donor pieces. 

This isn't such a bad thing.  Especially with the extra tenders you can sell online, people are always looking for them.  As far as the pancake motors go, I've never had a model with one, but I've heard nothing but bad things about them.  You might try developing your Model Railroad skills and try installing a new high quality can motor.

My own advice to you is to convert your layout to DCC as soon as you can and don't buy any DC locomotives.  If you have some already, Plan on installing DCC either yourself or by a professional (recommended). 

You can run your models purchased already with factory installed DCC with the default settings and have a lot of fun but after a while, you'll want to learn how to Manipulate the control values ("CV's"),  The first one I did when I converted was change the Whistle, but there's so many other things you can do with them.  I'll never forget the excitement when I first activated a full featured DCC command system on my layout.  It was like the sun came up.

There are umpteen videos out there how to change CVs, some are good and some are by windbags that like to hear themselves talk.  And when you do jump into the DCC pool, you can always come back here to ask questions.  I'm always here and there a number of other experienced modelers here who are always happy to answer your questions.

"Prototype" means the real life locomotive that the model is copied after.

"CV" refers  to variables within DCC that control a multitude of Operational functions and sounds.  I'm not very familiar with running a DCC/Sound equipped locomotive on a DC layout, But it's like wearing a shoe that doesn't really fit well, like a marriage of convenience in a way, not a whole lot of love there.  I believe some sounds occur, but the operator has no control over them at all, they just happen.

"Audio Assist" Appears to pertain to the TCS DCC decoder Which I'm not familiar with.  It Probably does not work on a DC layout.

Except.  Why the rear most derailed cars turned outward?  Maybe this was the rear of the train and the derailed locomotives were pushers.

That is one really sharp curve for the prototype, looks like on a layout almost.  What are all those horizontal things on the ground that look like another track? Welded rail laying on the ground?

Carts?  Like in a grocery store?

😂😂😂😂😂

If you told us which model you have, we could help you.  Bachmann makes several 4-6-0's in several scales.

The missing pieces are called crosshead guides.

Make new ones out of styrene stock to match the ones still on the other side.

I received a nicely custom decaled older Bachmann consolidation along with a bunch of other stuff I bought last year. The mechanism had been taken apart and we assembled badly and could not be repaired to operating condition.

 I just put the boiler shell on a new Bachmann mechanism and the tender shell on a new tender floor with a sound decoder.

https://share.icloud.com/photos/0ffriJqBPifUeeJpUPvT1bGbQ

I also have around 50 locomotives. But I basically started Model Railroading in the year 2007 after being out for 41 years.  Everything I had from 41 years before was destroyed in a fire a few years before.  So I basically started over in the DCC era. I have three DC locomotives, but they are all on hold waiting for decoders.

Presently, I don't run diesel locomotives, i'm modeling the 1930s, but I have around 15 I bought over time to run at some future time on another layout. The reality of model railroading today is that nothing is available very long, nearly everything is limited run in comparison to the days of yore.  It's a good thing I bought those diesels because none of them are available anymore.

Great.  Thank you!

Plastic or die cast?

1.  Consolidate
2.  Mogul

The KCS Southern Belle inspired paint scheme is beautiful and about to be lost, so much better than solid red.  Count it among the other lost ones like the warbonnet and the black widow.

If the view is looking west and slightly north, with downtown in the distance, this is probably the old T&NO (SP) crossing the old I-GN (MP).  I crossed those diamonds many a time on SP No. 2 and No. 5.  That was 60 years ago more, so nothing looks familiar anymore.

I wish that CPKC Would acquire L&A Ten wheeler number 503 that's rusting away in Port Arthur, Texas.

Putting the iron through a plastic shell was basically a joke.

But. Fill me in.  I've not been very aware of availability of separate DCC only Decoders without sound, and a separate sound only decoder. If that's the case, can one piggyback a sound only decoder onto an existing Silent DCC Decoder.  Please elaborate on this for my enlightenment.