The Bachpersonn eight-wheelers vary wildly piece-to-piece. The GF has one that will hold a steady thirty-five SMPH and pull twenty of the various MDC or Bachmann nineteenth century cars up a one per-cent grade. I doubt that the prototype would have done that. It will occasionally stall on a plastic frog switch.
I have one that can barely get out of its own way on level track and will stall on ordinary track. I have two others that run at about forty-five to fifty SMPH and will pull about six cars up a one per-cent grade.
The B-mann eight-wheeler is an 1850s/1860s era wood burner.
It is clearly not the best locomotive.
The Atlas/Micro-Ace mogul does run much better. It requires much break-in, but after that, it will hold a steady thirty SMPH, a speed that is about right for these things. It , too stalls on plastic frog switches. Only one truck on the tender picks up electric as well as the drivers The Atlas.Micro-Ace is an 1870s era model and is a coal burner.
The old MDC consolidated and mogul are late 1880s locomotives. MDC originally issued the consolidateds in colourful schemes, but the moguls came in black (although some of them had silver or grey fireboxes). The drivers on the consolidated are forty-eoght to fifty inches. The drivers on the mogul are sixty-three inches. If one were to update some of the details on the mogul, such as replacing the mantle-clock acetylene headlight and adding a generator and maybe a power reverse, one could use them on a pike with an era as late as the end of steam. The MDCs are excellent runners and pretty good pullers. Like the B-mann they have a motor in the tender and transmit power to the locomotive by means of a driveshaft. The tender does appear to sit a bit high, but this is a compromise with which I can live. The MDCs come as coal burners, but it is not difficult to convert them to oil burners. All tender wheels and drivers on both the consolidated and mogul pick up electric, although the traction tyred drivers do so less well than the others. The middle two pairs of drivers on the consolidated and the middle pair of drivers on the mogul are blind.
Athearn has continued the MDC consolidated. The Athearn paint schemes are more colourful and do look better. The Athearns also come with MT couplers, an improvement over the old MDCs which came with rapidos and MDC's less-than-useless knuckle coupler. All tender and locomotive drive wheels on the MDCs and Athearns pick up electric, although the drivers with traction tyres do so less well. The middle two drivers on the Athearn are blind.
If you do not mind pushing your era to the 1880s/1890s or even the early twentieth century, I would go with the MDCs.
If you must have Civil War era or 1870s, I would go with the Atlas/MicroAce mogul and use metal frog switches (and to the gapping/wiring required). It does appear that you could do some minor alterations to the tender and the stack to make a wood burner out of one.
