Thanks for sharing your views guys, your suggestions are all worthy of further study and considering. I need some better weather before I can put any of it to practical purpose. I shall update you once the temperatures rise!
In other news I have made a start on my momentum van. I began by stripping down the Zeecar mechanism. That was more of a challenge than I expected because I've only got a very small vice and there wasn't really room to position the mechanism between the jaws. I found centre punching the axles out from the wheels most successful. At this point I thought the axles were off centre on the mechanism body but on reflexion I now wonder if punching the wheels off may have shifted it even further. The picture clearly shows (on the uncut axle) that they were
off centre. It was clear that the body is quite flimsy and the axles are, indeed, free to move laterally by a small amount. Care, in fact great
care is needed. The CFLR is a 1'-11 1/2"gauge railway and so I run on 32mm track, my Zeecar axles were about 10mm longer than the IP engineering wheelset axles and so needed cutting down. With the wheels off I did manage to grip them in the vice. When I had finished I fancied I might have kinked the axle slightly, it had certainly shifted in the bearing again but once adjusted looked ok. The IP wheels were easy to 'de-axle'. They were an easy fit on the Zeecar axles, possibly a little too easy. The photo below shows the trimmed axles and the stripped down IP wheelsets.
On fitting the wheels to the Zeecar axles I detected a slight looseness but convinced myself that it would be ok once there was some glue on the axle. When trimmed for 32mm use there isn't a lot of axle poking out of the mechanism, great care is needed to make sure the wheel doesn't carry any glue back along the axle as far as the body. When positioning the wheels to make sure everything is equally spaced around the centre of the body there was a certain amount of shuffling of the wheels, double so when I realised there was still a very slight looseness, enough to risk a 'wobble'. Whilst juggling all these aspects of positioning I realised that glue had migrated a long way towards the body. I gave it a scrape with a blade and thought I'd got away with it. I now left well alone for 12 hours until the two part epoxy had properly hardened.
After an impatient wait my first concern was to see if there was any 'wobble' of the wheels on the axles. I gripped the body and a wheel with a view to 'giving it a spin', to my horror nothing moved, the glue had caught the axle in the body! I ran the blade around the axle where it entered the body and gave the axle a gentle tap and to my relief movement returned! My joy was short lived as both wheels were out of true, the one on the end of the axle I suspected may have been bent was about 3mm out, the other about half that. Clearly this would not do. Some gentle manipulation with pliers had no effect. Leaning back on all my permanent way experience, I picked up a hammer! it was only a small tack hammer and (for a pway man) I wielded it very gently. Some carefully aimed taps to the outer side of the wheel rims followed. This really was a case of 'slowly, slowly, catchy monkey'. Taking it a little bit at a time I managed to get things back into true. I'm satisfied there is no more than 0.25mm of wobble on either wheel now. As the axle also still runs pretty true I am more inclined to think that there was some deformation of the axle during the shortening process and that the movement of the wheels on the axle was a very minor component of the problem.
I had toyed with the idea of mounting the mech on the van floor with a chain drive to the IP wheelset, however, when I looked at the van assembly it looked feasible to use the Zeecar axle so I thought I'd give it a try. A hole was cut in the floor to accept the mechanism before construction started. The build of the body has been progressing all week. My kit building experience in this scale is virtually non existent, this is only my second one. I'm 90% of the way through building a Brandbright hopper wagon. I was thoroughly impressed with this kit, the standard of the components, the clarity of the instructions and the way the kit went together. I like my vans and coaches to be as tall as my (Accucraft) locos so I am always looking for the taller items of rolling stock. The Brandbright brake van looked good but the IP version had an extra 10mm of height so I went with that. It's a nice kit. Subtly different in all aspects mentioned to the Brandbright kit. I fancy there might be slightly less detail but without comparing the two it can be no more than a gut feeling. I may see if I can persuade someone to buy me a Brandbright van for my birthday to have a go with. I certainly want a second momentum van so this may be the second project. I'd like to try a floor mounted, chain driven version of the Zeecar mech and I also have a smaller and slightly less resistant mech out of a Glendale Express toy that I'd like to try - all in good time though! The final body assembly stage of the IP van is sitting on the bench gluing as I type. I'm hoping I might get down to the actual installation of the 'momentum' into the 'van' over the weekend. I'll keep you all posted of course.