In N scale, there isn't anything like the range of models that you get in HO, so you take what you can get. Pacifics are very short on the ground, at least those suitable for my neck of the woods - in fact the list begins and ends with exactly one model, the Model Power USRA 4-6-2. And even then, I don't know how particularly accurate it is since MP seem to use the same body casting over their USRA 2-8-2 as well.
Never mind, though, I fancied one so earlier this year I picked one up off ebay. I'd heard decidely mixed views of the Model Power locos - it was said that if you got a good one, they ran really well but the pickup arrangement was hit and miss. Also, they aren't DCC ready, requiring a hard-wired decoder. I had also had doubts about the moulded handrails and a tendency for the cab to look a bit droopy in some of the examples I'd seen - but as I say, you take what you can get and the wheels and motion looked well up to scratch.
When I got my model I was suprised at how sloppy the loco-tender connection was - it seemed to be retained only by the wires, with the drawbar doing nothing. When I eventually opened the tender to look at the wiring, I could see that a small plastic spigot was missing, which gave the drawbar nothing to hook over. I fashioned a replacement from plastic rod. I then tested the model on a short stretch of DC test track. It ran very slowly and smoothly, if a little noisier than a contemporary Bachmann model.
There matters rested until I found the nerve to wire in a Lenz silver mini decoder. It turned out to be relatively straightforward, provided I accepted the headlamp being on permanently. Dismantling the loco, to get at the headlamp wiring, is apparently a significantly harder job so I kept well away from that.
However, the model ran terribly on the layout. It was still smooth and controllable, but it stalled at every opportunity. It turns out that the Model Power pickup arrangement is quite poor - a straight length of plain test track is no substitute for a layout with pointwork, curves, etc! The tender bogies are each live to one rail, so you're only picking up from two wheels at a time. Yes, there are pickups on the loco but the wheelbase is short and the problems seemed to happen when the loco was going over point frogs, leading to the driving wheels dropping slightly into the crossing. At that point the tender is doing all the pickup work and it's not sufficient.
Trawling the internet, I read that some people had done a straight swap with a Bachmann USRA tender, which has a proven and reliable eight wheel pickup arrangement. That seemed like a good idea, and Bachmann tenders are relatively easy to obtain, so (again to ebay) I got myself a spare. (I actually ended paying more than if I'd gone straight to Bachmann's spares department - lesson learned, there). But that was about 6 months ago as I couldn't immediately find a way to dismantle the Bachmann tender. I kept putting it off, never quite feeling up to the job of transplanting the decoder and sorting out the wiring and drawbar connection to the new tender. I think partly it was the fear that if this didn't work, there were not many other options.
As it happened, with a freshly tidied layout room, I felt like giving it a shot and it turned out to be one of those jobs that was much, much easier than I expected. Dismantling the Bachmann tender - a snip, just needed to be a bit more forceful. Inside, everything unscrewed very easily and the Bachmann wiring convention was very straightforward. I made a diagram just to be sure and then snipped and resoldered the Lenz chip into the Bachmann chassis. I also found that - thanks to a cunningly placed screw - it was a matter of seconds to work in a new drawbar connection. The model was tested and the difference in performance was fantastic - not a stutter or stall, even with the pickup coming entirely from the tender. I then reconnected the loco pickups as well, just to be 100%.
The only remaining job is to hack a bit more plastic away from the Model Power tender shell so that it can sit nicely on the Bachmann chassis - you can see it riding high in the pics - but if that fails, I still have the undecorated Bachmann tender shell as a fall back. The only thing I've discovered tonight is that no one seems to do Southern steam locomotive decals in N. Bit of a surprise, that, as I have a couple of other steamers I'd like to paint and/or renumber.
In terms of the body detailing it's still a bit of a mixed blessing, the MP USRA pacific, but it looks nice and purposeful and it is very heavy, being all die-cast. I think it will look good pulling some Southern green heavyweight coaches and from normal layout viewing distances, those moulded handrails aren't going to matter...
Cheers and thanks for reading.