The first and quite probably the only ready-to-run British loco for the railway is one of the Warship models by Fleischmann, D818 'Glory'. I never really imagined the layout could take a mainline loco but this will just about fit into both headshunts with one short wagon. It will also be useful for services along the length of the layout to the extension at 'Fairport'.
I have rebuilt the model with new wheels, simpler wiring, the body lowered onto the bogies, and Kadee couplers.
Stage 1 - Wheels
As supplied, the model is a good 1:87 scale representation of the prototype but the whole body sits about 2 mm too high on its bogies - this makes space for the usual over-scale RTR wheels. So the first stage of the rebuild was to change the wheels. I used a set of Ultrascale 11mm '00' wheels with their 'H0' axles. These wheels are marketed as "2 ft 9 in" for 4mm scale, but if the Wikepedia entry for the Warship is accurate and the original wheels really were 1003 mm diameter (I guess, when new) then 11 mm is close to the scale 1003/87 = 11.5 mm, and the underscale diameter should help getting the body down to the proper height.
a. The original wheels pull off their axles, thumbnails are strong enough to do this.
b. The original gears are moulded onto the backs of their adjacent wheels. To take them off, I clamped the wheels in the vise and cut across with a scalpel blade, then cleaned up the cut side of the gears. Then I pressed the gears onto the new axles, they are a tight-ish interference fit - good
c. The new wheels are a lot thinner than the originals so I added some washers as shims, this makes sure the pickups stay in contact with the wheels. Then I used the vise to press the wheels onto their axles, pressing and turning the wheels a little at a time to help make sure everything ended up square.
I reassembled the chassis, gave a test run and everything worked fine. The driving wheel and gear assemblies will need glueing up before the loco hauls a train, but at the moment it carries itself along. Old and new wheels:
Stage 2 - Wiring
The original wiring uses the chassis as the return conductor for the headcode lights. I removed this connection (and the lights) so the chassis is no longer a live conductor, and so it cannot cause a short circuit if the wheels touch the chassis on tight curves. This is important for any future conversion to DCC.
Stage 3 - Lowering
I used the method devised by Phil Burkett of the British H0 Society and described in issue number 58 of their 'Satellite' magazine. This works well, my variation was to use strips of brass instead of styrene to hold the bogie mounts. The brass strips are Araldited onto the chassis.
Step 4 - Kadee couplers
With the body lowered, it is easy to fit "standard" Kadee couplers.
I tapped the existing holes M2, and used an M2 screw to hold the new coupler in place - this is the Kadee #158 (the "scale head" whisker coupler, main dimensions same as their traditional #5) - the height comes out perfect, without needing any further adjustment. At the motor end, I shortened the draft gear box to clear the motor bogie:
As a confidence check, the model runs through my turnouts built to 00-SF standards, Peco code 75 "fine standard" points and Peco Setrack points (code 100 with huge flangeways) - all without any problems except the obvious wheel drop on the Setrack.
I'm very pleased with this.
Postscript (31 May 2016)
Trying out the loco on my reverse curves I had a consistent buffer locking problem and I have replaced the #158 couplers (above) with #146 ones - standard head, long shank. These couplers are longer than I would really like, but at least they work. Scale head ones would look better.