Horsetan

Are you planning around High Level standard hornblocks, or their spacesaver (thin, in other words) ones?

I got a broadly similar result on the spreadsheet, so it looks like you're on target. NWSL make a lot of stuff to order now, rather than holding stock of every single part, so it's a matter of ordering and waiting, especially given average international postal times these days.

It will work if you make your drivetrain articulated, in other words the gear positioning is allowed to swivel, and thus not interfere with the vertical movement of the axleboxes. The QuadDriver is a start, and if you look at the High Level gearboxes, some have an articulated section to the final drive, and there's also a DriveStretcher option to cope with more awkward layouts. If High Level don't have exactly what you're after, do have a look at NWSL. USA-based, but they have a bewildering range of gears, from 0.2 to 0.75 MOD, and loads of other things that may be adapted. They even do bevels and a multi-start worm which is effectively a cross-helical, which is brilliant if you want a low-resistance non-locking drive.

Shouldn't be too difficult to convert back to the correct gauge.

I'm wondering if this might be a suitable place for a modern version of Rivarossi's S-drive system?

If the etch can be built as a "421", I'm in for a 21mm gauge version. Subject to what I wrote about providing half-etch lines for the HL hornguides, I can work out my own fulcrum points for the CSB spring beams. I'm only really interested in trying to build preserved stuff, because the option exists to actually go and see it.

High Level gears are not a particularly fine pitch; they are likely to be around MOD 0.5 to make them easier to mesh. They are available individually as spares, so you could buy a set and experiment with the permutations. Ultrascale also have Apple-based gear calculators that help you set centre distances, etc. There are CSB calculation spreadsheets available for download - to get the best out of them, you need to have some idea of how much your model will weigh, and where you think the overall centre of balance will be. The one I have linked to has tabs for 4, 6, 8 or 10-coupled chassis.

Example here As far as Irish coach etching lists are concerned, you have to register with the Mousa Models site before you are allowed to download, but I don't think you're missing much if my downloaded copy is anything to go by. Mousa-Models-Etch-List-Coaches-Pre-Grouping-Irish.pdf

If anyone has a basement or similar well-drained sub-surface accommodation, now might be a good time to use it....

I've always thought the Maybach E a somewhat unbalanced design, but it did get into preservation, and I wouldn't say no to having a go at an etched one. How many etches are you planning to produce, and what would the cost be to an interested customer like me? For compensation/springs, the current hornguide standard is the High Level one, so your chassis etch should have provision to cut out a 5mm wide slot so that the HL guide will slide in and be held in place accurately for soldering. That just leaves me to work out the fulcrum points for CSB springs. Effectively the uncoupled chassis could be treated similar to a diesel bogie - you can decide whether to drive only 4 or all 6 wheels, but this should ideally be done as a separate gearbox or series of boxes, so that it doesn't interfere with the action of compensation or springs.

What is the method for unclipping the bogies for re-wheeling / regauging, please?

Mousa Models is Bill Bedford. Unfortunately his production is erratic at best nowadays, and it's never entirely clear from the website what he has available or what he can make available. When he has a trade stand at finescale shows, it's best to just buy what you can see, 'cos the chances are that you may not see it again. Note also that he hasn't lived in Shetland for years. He has resided in Leytonstone, above the former premises of The Engine Shed model shop...which is now a hairdressers.

It occurs to me that it could still be sprung using the Dave Bradwell spring carriers.

I wouldn't mind a couple in 21mm to see what they're like...

I also saw a suggestion that the N gauge couplings be replaced with the much less-obtrusive Märklin Z-gauge/miniclub ones.

For coaching stock, yes. For freight, it might be a bit different. The Accurascale semi-transparent couplings could have gone further, and been made fully-transparent. Maybe something could also have been done to reduce the massive gap between coupled vehicles.

If there's any left over, I might be interested in one or two if that makes things easier....

Gostude has a collection of Studebaker cars to support.

Not so much alternate universe as naked greed.

Thurles Is Not Enough

That's a bit like BR Mk1 underframes being used as car transporters for the Motorail service

CIE Another Day

I have a Park Royal on order as well. Spare 8' Commonwealth bogies would be useful - they would go under an Irish Freight Models Laminate kit that I have.

That's what I bought four spare bogie pairs for (when they were on a discount offer): to go under the Murphy's RPSI Mk2 trio here. The bogie pivots are obviously not the same, so a good deal of improvisation will be needed. Murphy Mk2s are difficult to dismantle and, despite a few goes at it, I haven't managed to prise the bodyshell off the underframe. The other thing is the conversion to 21mm. The back-to-back for P4 profile wheels comes out at either 19.67 or 19.87mm depending on whether your flangeway gaps are dead scale or not. IRM Mk2 bogie wheels are mounted the same way as is common in 2mm finescale: the wheels are "live" with pinpoint 1.5mm split axles held in an insulating muff so that they can conduct the electric needed for coach lighting. Most P4 coach wheels have plastic centres on a solid 2mm axle. On the face of it, this won't work properly in an IRM bogie as the lighting circuit will be lost unless you can arrange extra pickups to "wipe" the tyres without touching the axle and a standard P4 axle is usually too short for 21mm gauge. Having messed with the problem over many weeks, my thinking is that the IRM method has to be replicated, so: - live P4 wheels and tyres (12mm diameter steel, available from Alan Gibson Workshop); - wheel centres sleeved down from 2mm to 1.5mm (if I can get micro tube for it); - IRM 1.5mm split pinpoint axles and muffs if, and it's a big "if", these parts are also available as spares. Yes they have been allocated part numbers in the IRM instruction diagrams but I need to find out if they can be supplied.

I wonder if they'll be able to find sufficient drawings for it, though