I'd also think there is some kind of mech issue,irregardless of possible decoder problems.
I don't have the DCC version,but my DC 2-8-0's will pull over 30 hoppers on the straight & flat with no problem at all.

http://www.piedmontsub.com/Hopper.shtml

I think this should answer the question...

Tony:
Recently got my first ten wheeler and found your assesment "spot-on".
Mine had all the problems you mentioned, and the "fixes" worked fine.
It runs quite well now.
Interestingly,  I have a problem I hadn't heard of yet- on mine, the headlight only lights in reverse...
I used the short USRA tender underframe with a new "bashed' body,
and removed the DCC chip per Bachmann instructions.
(I'm using DC only on this)
The plastic pins used to secure the brass pick-up strips had been so overmelted as to ruin them, leaving the strips near to or falling off.
I went to the trouble of replacing the pins and doing it myself...
All in all it's a nice loco I've wanted for decades, but I'm glad there are people like you around helping trouble shoot the things...

Interesting. Thanks very much for the added info.
From what we "know", it looks like (if not certain) batch 2 would have had the USRA (works for me) style truck too.
BR&P construction "batch 3" was 710 to 740, so maybe the truck style changed after 725.
(the photos of 3rd. group locos I looked at with the delta truck were later than 725)
It might be one of the reasons B&O broke this group into 2 sub classes at that point; I'm pretty shy of info from the B&O years so I don't really know. I guess I should try to do something about that.
Would I be correct that the KK4d would be the heavy frame jobs; 741 to 755 then?

In any case, it seems we can do many of these without replacing the trailing truck; for either road.
It doesn't help for the "heavies"; which were (I've read) the only ones the BR&P usually double headed...
So it goes. And hopefully, Model Power will come through with more locos & parts soon.

Skipgear:
Been looking at my photos of the LL/KK4 class locos & stumbled on something interesting with the trailing truck.
Do you have any pics of the early production locos from the first batch? (700 to 704/7504)
I have good ones of 701 (builders shot) and of B&O 7504 in 1949. Both have trailing trucks that seem to more resemble the one on the C&O H-4 class. (sorry, I don't recall the name of that type)
I have none clearly showing the trailing truck on batch-2 (705 to 709)
All the pics I have of batch-3/4 have the familiar Delta style truck.
My eyes could be tricking me; but could it be that the stock truck is better for at least the first  batch of these locos whether on the BR&P or B&O?
On another note- do you know the Model Power part number & if they still have the Delta style truck?

Quote from: johnTom on April 10, 2010, 09:42:58 AM
The XX class mallets of B.R. & P. RY were 2-8-8-2's, not 2-6-6-2's.

Yes, I'm well aware of that.
It was just a comment in regards to the boiler top air tanks & when they started showing up.
Guess I should have been more specific in my post.
edit-For what it's worth; the LL's got the boiler top tanks in "early" 1929 according to Mike Z's book.

Yah,use the new H-4 for the front cylinders. Sell the vandy to a C&O guy-I hear B'Mann wants a mint for it
New tender, modify the cab roof, move the pumps etc and some other details should get it pretty close.
Some of us "early" BR&P modellers (half a dozen? )don't need the tanks on the boiler top; those came  later on the LL's.
I don't remember the year anymore. Seems to me they were origional equipment on the XX's though...
Be nice if Bachmann did a BR&P/B&O version for us; there were 55 of them after all...

If any help was given. you are welcome.
I haven't started my new layout yet; last one was over 15 years ago.
In the meantime, I run on a club "N-Trak" set-up now & then.
Right now, I'm waiting to see the new version of the 2-6-6-2 when it comes out. It sounds like we both have some time to be patient...

BTW & off-topic-I assumed you are a "Trek" fan from your sign-in?
Got hooked myself in the first run/origional series; way too many years ago...

Understood, "earther"
If it helps any, MB Klein is an old and highly regarded "brick & mortar" hobby shop in Baltimore that also does on-line/mail order sales.

Do you need a specific roadname, or want to avoid ordering on-line?
(I can understand that)
The first place I checked was MB Klein; they had 3 dozen in stock at a very good price...(as of 11:45 AM)