Perhaps the problem is the track. I built a small 4x8 layout using Trutrack. I experienced some derail problems with one loco going into an 18" radius curve. It is a light mountain and I know some of you will deride my using such a loco on 18" track but it is designed to take such curves. It is my largest loco and yes my Consolidation looks more the correct size but I like the light mountain and after all it is my railway no matter what CN has to say. I do have 22" on the main loop.  I had electical problems with the turnouts when I converted to DCC but they and all my track issues went away when I changed all of the track to Kato Unitrack. It is a far superior product. The problem I found with Trutrack is that you can't eliminate gaps at the rail joiners. Also the turnouts are poorly made. No such issues with Unitrack.
I have noted comments in this thread and many others criticizing the 4x8 layout. I agree there are limitations but saying you should go around the walls instead, as it uses no greater footprint, assumes the access aisles beside the 4x8 have no other use but board access. That isn't always true.
In my case my layout is in a 600 S.F. room but  the access aisle on one side is also the access to a large bookcase. On the other it is the "pathway" to the furnace room and also to my wife's harpsicord so a board is the only option. Quite frankly I was lucky to get that space as the CEO didn't have a model railway in mind when we remodelled the room a couple of years ago.

Gene,
I guess I should have been more explicit. The only difference was the height of the coal load. The 0-8-0 has a higher coal box(?) so there isn't much room for the speaker in the 0-6-0, at least in my version. I couldn't use the speaker baffles.

I recently put in a Soundtraxx DSD LL080LC decoder in an 0-6-0. It is supposed to work the same as with the 0-8-0 and is advertised as plug n play.  The tender is smaller so in fact it was more difficult to put in the speaker, but I did it and as this was only my 3rd install and the first that required a soldering iron, I was very proud of myself. Everything worked fine. As they say just go for it.
A word of caution though on this decoder, I can't get rid of motor hum and it turns out this decoder is an older design that doesn't have back EMF. The hum is just way it is. I was able to reduce it but I find it annoying.

I did a layout very much the same last year using DC.
The common rail only needs one lead but you can use more, I used one for each loop, the inner and outer connected to the - terminal of the power pack. There shouldn't be any insulated rail joiners on the common rail.
The positive went to the Atlas Controller and then there was one lead to each block for each switch on the Controller. It worked just fine.
I have since torn up the entire layout, changed to Kato track and gone all DCC.
If you want to know why just ask!

Great job!
I have one of those and was wondering if you had posted pictures and info last year on the DCC install. I have just joined the DCC world and would like to install a decoder in mine. I can follow directions but don't have the knowledge to plunge in without guidance.
Thanks.

Bachmann sells seperate tenders so why not sell a version with the sound decoder!
I'd buy several.

I sure agree that we need a Pacific and not PRR!
They were great locos. The CPR had plans to build 600 of them in the 1940's which shows what they thougth of them. Only a little over 100 were built and these were probably the last Pacifics built in North America with the last being delivered in 1948.
Now I doubt we will ever see a Bachamann model of one but I would be happy with any Spectrum Pacific.

My latest is a Spectrum 2-8-0 with sound. It started out as a Southern loco but now is CNR. Must say I'm impressed with the looks, operation and sound!
I also have a light mountain and a decapod.

 Being new to DCC and the installation of decoders, I put a Soundtraxx plug 'n play that was designed for this loco or the 0-6-0, into an 0-6-0 last month.
The operation is ok and the sound, while not great is acceptable, but what really surprised me was the loud hum from the motor.
Turns out this is par for the course with this unit as it isn't back EMF and although I adjusted CV9 as recommended by Tony's Train Exchange the hum is still there  but at least not as loud. A search on another forum confirmed others had the same issue with this decoder.
Just a word of caution if you are tempted to use one of these.
I doubt I will use this loco much until I can find a new decoder. $65 down the drain.

It was adivce from SteamGene that helped me do my first install as I mentioned in my first post. Thanks Gene!
It was very easy to do just as he says. I used a mini-steam #1639. You can even chose from 10 or so different whistles.
However I don't think you can change CV's with EZ Command.
I also got help from the Saskatoon Railroad Modellers web site. Just look for the info on doing a decoder install in a Consolidation.
I got restarted in the hobby after a 45 year interval a little over a year ago.
I took out my Penn Line Consolidation out of storage, oiled it and did run but it is a rather crude loco compared to those now. I thought I would just
stick with DC but then I bought a sound loco and from then the conversion to sound and DCC started. For me it brings the whole layout to life.
Again thanks to those on this forum for all the help you didn't realize you were giving me.

I purchased a L&N Mountain from Kleins last year and it is a great loco with very good detail. I saw on there web site a little while ago that they still had some left.
Adding a DCC decoder is a very simple plug-in. Just search for the notes on installing a decoder in a Consolidation( same tender).
I installed a plug-in sound decoder as my first decoder installation and it was very easy. I used a MRC mini-steam and so far it is working fine. I am aware that there have been problems with some MRC decoders but as they say " the price was right".

After a 45 year hiatus I got back into the hobby last year.
At first I just went with what I knew , i.e. DC but the sound bug bit and now
I have successfully installed a decoder in a Light Mountain thanks to all the information I obtained from this forum.
I cut the capacitors as recommended and now I am about to install a decoder in a Russian Decapod. However I can't find any information as to whether or not there are capacitors to cut on its circuit board. There is a
small orange object that is similar to the capacitor on the Light Mountain board but it is smaller and a different shape.
Is that a capacitor and should I cut it?
Thanks in advance from the Great White North.