Here's my Comet Dean Goods, which has finally reached completion after quite a protracted saga, involving more motor swaps than an F1 team.

As mentioned in an earlier entry, I acquired the loco and tender chassis in an assembled state from another Rmwebber, who kindly did me a very good deal on the parts. This was perfect timing as I'd recently failed to install a decoder in my own Dapol-era Dean Goods, and was considering the possibilities of a proper loco-drive chassis substitution. At the time I thought that once I'd tweaked the pickups, there wouldn't be much more to do. As it happened, there was quite bit more to be done!

The first snag I hit was that the chassis had been screwed to a Dean Goods body which had been filled with some sort of shot pellets to add weight. Unfortunately, as has been reported in MRJ in particular, there can be a reaction between these pellets and PVA, leading to a progressive swelling. In this case, the effect had been enough to rupture the moulding between the boiler and the firebox, as well as the smokebox, and this in turn had led to the body turning banana-shaped, which was in turn stressing the chassis, bending it out of true. While Comet chassis are designed so that the center axles sit a little higher than the outer ones, in this case the flanges of the middle wheels were clear of the top of the rail. The running was lumpy at best since the distance between the wheels no longer matched the coupling rods. I tried squaring up the chassis but eventually decided that it would be neater and simpler to solder up some new frames.

So - I ordered a new frame set from Comet. This was assembled in an evening and the wheels, motor and gearbox from the original chassis were quickly transplanted, along with my own pickups. The model now ran better than before but was extremely gutless, stalling under any kind of load. The wheels would not slip, which to me is indicative of a model with insufficient power. I concluded that the Mashima 1015 motor must have been overloaded during the test running of the warped chassis, and therefore ordered new one. The only provision I made before installing the new 1015 was to cut off the rear motor spindle with a cutting disk. Optimistically, I tried the loco out again - only to find out that it was barely any better than before. It could cope with a load at speed, but was useless at the typical plod of a goods engine, slowing to a crawl on curves and still not able to spin its wheels. Had I damaged the motor with the cutting disk, by dwelling too long? What the hell, get another 1015. This time I put the motor in without removing the spindle and was surprised to find that the body still fitted. But again, the performance was unsatisfactory. At this point I'm on 1015 number three! Following a discussion elsewhere on the forum:

http://www.rmweb.co.uk/community/index.php?/topic/90035-mashima-1015-motor-low-torque-problem/

I decided as a last resort (other than assembling a new gearbox) was to try the more powerful 1024 in the same location. The 1024 clearly fits the available space, and with some ingenuity it might not even be necessary to remove the spindle. I test fitted it and the transformation in running was immediately noticeable, with a smooth performance at low speeds and plenty of spare torque to spin the wheels.

Not being able to find my cutting disks to remove the spindle, I resorted to something I've been told by at least one knowledgeable Rmwebber is totally impossible - snipping through the spindle with pliers. I used a heavy pair of the kind we tend to keep around the layout for stripping wire, snipping through cables and so on. Once again I got through the spindle in one clean cut, with no risk of heating the bearings or unseating the motor parts in any way. Yes, it takes a bit of oomph but it can be done. Or rather it can't, because it's impossible...

With the chassis now running well, I began transplanting the brake gear from the old chassis onto the new one. Having it all soldered up already made this a very quick job, and I was careful to test the chassis after adding each element, to make sure there was no contact between wheels and brakes, pull rods etc. With the chassis now ready for painting, I can push on with upgrading the body and tender - removing that hideous coal load, etc. As the moment the model is running on plain DC but if I choose to paint the Dean in BR black, it'll need a decoder - there's bags of room in that tender, though.

At the end of it all, I'm very pleased with the model. Although there have been a few frustrations along the way, I certainly learned a lot and the Dean looks beautiful when running. I'm not against tender drives at all when they're mechanically sophisticated and don't impede on the looks of the model - look at Roco's SNCF Pacific for how it should be done - but in the case of the Dean, the mechanism really did spoil the elegant looks of the original beneath the tender running plate. Mine was also a bit of an intermittent squealer (oddly, the tender drive units in the ex-Airfix 4F and 2P seem much less prone).

So you there you have it - a Dean Goods nearly ready to return to service. Now I have two or even three 1015 motors which need new homes ... so unless anyone's after one (PM me, of course) I'll be keeping an eye out for additional projects which can use these motors at the high revs for which they're engineered.

Cheers! (And apologies to 10CC).