You could call the repair center first and see what they would say. Just saying.
Contact info in Parts, Service and Information page.

Rich

It should run on address 3.

Rich

Post a photo. A photo is worth a thousand words,
Edit. If you not aware. You will need a photo hosting site to post photos.

Rich

Welcome

You can do a reset. CV8 enter 8. Cycle track power. Headlight should flash sixteen times.
Also check CV page.

https://www.bachmanntrains.com/home-usa/dcc.php

Rich

No idea. All I have are the standard edition 4-6-0's.

Rich

Have you called the Parts department for the proper part?
I had to do that about eight years ago, They sent me the proper pair of connectors with a bill.

Rich

Not that I am aware of but you could check the parts page. The decoder is a PC board that is wired to the pickups and speaker that is in the oil tank. Not a simple plug in.
You could check the Soundtraxx page and see if the have a suggestion. They have a decoder selector for Bachmann locos and speaker
The two suggestions are solder in.
The TCS site is solder in.
I assume yours is an eight pin socket.
Others will suggest.

Rich

Maybe someone here can tel you if the other locos have the same parts. Notice the worm is separate. It drives a worm gear on each truck, I use Labelle oil and great with WTFE witch helps a lot. I get the kit from Amazon.
I make sure nothing, gears are rubbing. A drop of oil on each motor shaft at motor.


Rich

Well, first of now you need a photo hosting site.
Below is site should help  you. The loco has a split chassis.
The wheels could be out of quarter or side rods not correct.

https://tcsdcc.com/installation/ho-scale/1229

Another diagram

https://hoseeker.org/assemblyexplosionbachmann/Bachmannspectrum462k4pg2.jpg

Rich

If your loco slows down the further it gets from the pack, usually the issue is track or wiring to the track.
That happened to me with my first layout many, many years ago using sectional track.

Rich

It sure does not look like it. They both seem to have a flat bottom.

Rich

That is probably impossible to do
Some years ago I had to order the two cables for a different Bachmann steamer.
Check the Parts page for this loco. You should find the cable and connector. Replace it paying attention to each wire.

Rich

Quite a bridge, yard at the time. Looks a lot different today. Strange. Nothing was happening when the photo was taken.

Rich

I have always been curious. I do a lot of searching on the Internet for many thing.
Slight chance you might find something on ebay.

I use DuckDuckGo for a search engine.  An add on for Firefox. It does not track you like Google does.

Rich

Can you be more specific? Maybe a photo or two? You will need a photo hosting site.
I just did a search. I found a number of links and photos.
Maybe it was produced about 1970's. A guess.
I did find this. Maybe you can compare. Check ebay.

http://www.spookshow.net/loco/bach040.html

Rich