Not really a lot to say on this, other than its a much more difficult conversion than Clan Line was. The big problem at the moment is that there is not enough space inside the splashers to fit the new wheels. Off the top of my head the 'front to front' width of the new wheels is 22mm, the rear and centre splashers have a clearance of 22.5mm between them, whereas the front wheel only has 21.5mm clearance.
I can see 4 possible courses of action:
1) give up - not really an option given that it will take so much effort to rebuild the chassis to get the loco in a sellable condition, unless I could make back what I paid for it this just isnt an option.
2) file out the splashers to get more clearance on each one, by my reckoning the middle and rear splasher are each about 0.8mm in thickness, I hope to be able to reduce this by half without weakening them too much (thus getting 1mm or so clearance on those two axles). The big problem is the lead axle, while the rear/centre splashers are attached to the boiler, the lead one is attached to the running plate (thus a lot harder to remove and less of an indication as to their width. in order to get enough materiel removed I am worried that it will go through the plastic
3) I know that with other wheels Gibsons are often a bit wider than the alternatives, it would be interesting to know the width of the Ultrascale option. The final option would be the Exactoscale product (which from experence are normally a scale width and will fit where other wheels wont. But I doubt they could be made to work with the Hornby chassis
4) which leads to option 4, by far the most expensive option, use the exactoscale wheels along with an etched chassis
For the time being I think the best course of action is going to be to put it all to one side and concentrate on other projects. Firstly I really should find out just how well Clan Line works before starting another large loco, secondly the Hornby A3 chassis has taken a backward step from that in the MN in that they have got rid of the sprung rear axle. This does result in a bit of a worry as to how well a completely solid chassis will run (baring in mind that it has 4 fixed axles). Tis all a bit of a shame really, as I really fancy getting a Castle at some point and that suffers from the same issue what wheels probably wont fit.
Hopefully Gibson will soon have the drivers for City of Truro available and I can get on with converting that instead!
A quick question, just to set my mind at rest. what should the distance be between the outside face of the splasher and the outside edge of the plate it sits on?