QUOTE (Fireline @ 3 Nov 2008, 12:37)
<{POST_SNAPBACK}>I don't want to massively increase the top speeds, but as I model a preserved line, I would like to be able to run the engines from one end of my line to the other a lot quieter than I can now with the present gearing. All I want is to be able to create a similar gearing to the recently updated Jinty. I certainly don't want to model 100mph running with a Terrier!
Of the two models mentioned, I only have the J94. For such a basic mechanism it can actually be got to run quite sweetly and quietly under DCC control (Lenz silver in my case) with extra weight on board; most of the cast ballast having been replaced in lead. As an aside, unless your preserved line is the GC section near Loughborough, top speed n the UK is restricted to 25mph under the light railways act. And the maximum speed of the model as supplied well exceeds what the prototype would be capable of, mine would get up to a scale 90mph.
To improve on the drive, it would be possible to replace it with a fold up gearbox and better motor. Branchlines, Comet, High Level, and doubtless other makers; all will have combinations of box, gearing, and motor to fit and deliver whatever improvement you seek. That would likely come in at similar cost to the purchase price of the complete loco. There may even be a kit to build a replacement etched chassis, with more accurate wheels as well, if you want to go the whole hog on the mechanism.