goldfish

Its all those cogs whirling around, they need to be lubricated but they fling oil everywhere.

If you are using the track purely for clockwork is there actually any need to clean it? Other than for purley cosmetic purposes. The usual source of dirt from clockwork is oil, it doesn't matter how careful you are to keep it away from the wheels it still gets on the rails.

Did you have the same problem without the couplings? I know from personal experience that you can push Stroudley 4-wheel coaches though unmodified Peco Setrack points with a Terrier without problems, and that is with a reverse curve. The "footprint" of a wagon wheel is about 12mm and the check rails are 30mm+ long which should be long enough to guide the wheels through the frog.

Out of curiosity, have you tried loose shunting your stock through these points without couplings?

What better way to start the day, than with an over the top AI description and an over exited seller : - https://www.ebay.co.uk/itm/335322814448? I always thought FLAWLESS meant without flaws. Don't paint chips count as flaws?

It is 0 gauge tinplate, so it must be Hornby : - https://www.ebay.co.uk/itm/204720510778? Pity about the prominent Bassett Lowke logo.

Another chiseller looking to make a killing : - https://www.ebay.co.uk/itm/266733347373? The price is about twice that of a set in reasonable condition. "Loco runs but very slow, needs some oil and service." is probably short hand for the piston in the smoke generator has succumbed to mazak rot and the mechanism is slowly destroying itself. The box lid looks like it has seen better days as well.

Maerklin also used 26mm gauge and called it 00 Apparently based on the locomotive Maerklin made for Raylo.

Better to stay in imperial. I make 3mph to be 4.4 ft/sec. A 65 ft turntable has a circumference of 204.2 ft. So one revolution takes 46.4 seconds. So 1.29 rpm. In reality it can take a lot longer : - https://www.youtube.com/watch?v=fLL-SExCHTc (2:36 - 4:39)

Rails of Sheffield are currently offering "Dapol 7P-020-CLUB1 Set of 3 Stroudley 4 Wheel Suburban Oil Lit Mahogany Passenger Coaches" for £179.95. Just the thing to go with your £125 Terrier. https://railsofsheffield.com/products/set-of-3-stroudley-4-wheel-suburban-oil-lit-mahogany-passenger-coaches

Possibly because they are comfortably past their three score and twenty, and failing eyesight and reduced manual dexterity mean that more prototypical couplings are physically beyond them?

There is no reason why for there not being an equivalent to the tension lock coupler in 0 Gauge, about from a lack of market interest. Indeed 00 tension lock couplings can be used with 0 Gauge with reasonable success. These are Bachmann (?) 00 couplings mounted styrene strip fitted through the 3-link receptacle. Actually a discarded project because simple drop links are more reliable and much less trouble. All that is needed to prevent buffer lock is to keep the buffers from interlocking, and that requires some reliable means of maintaining them at the correct distance apart. Realistically anything bigger than a Terrier or a 4-wheel coach is unlikely to work on curves smaller than Peco set track, although tenders are reasonably short wheelbase and that can help solve the problem.

Would these qualify as exceptionally tight curves? Not fine scale, but fine scale compatible. The points are 170mm radius, and the wagons can be pushed through the points in all directions. It is just a simple matter of using appropriate couplings. In this case over long swivel, drop links. The track is ETS Tram Track and so has check rails as standard.

I was simply pointing out that it is a very conservative design criteria. It is reassuring that you are designing for smaller radius curves, perhaps you should try the 88DS through ETS 627mm radius points, the Dapol Terrier manages surprisingly well. In reality almost any 0-4-0 will run around 2' curves, the problem is getting them to do something useful, and that almost certainly requires the couplings replacing to prevent buffer lock. The Dapol Sentinel Shunter is perfectly at home on 2' radius curves, so the 88DS should be equally at home.

According to the Accurascale website the Ruston 88DS has :- This is an incredibly conservative minimum radius to be using as a design specification or consideration for this type of locomotive. In fact it is equivalent to designing a 4mm version to run on radius 4 set track. With such a short wheelbase it would be able to traverse ridiculously small radius curves, although it would be reduced to doing no more than chasing its tail on them. It would certainly be perfectly be capable of running through the 24" / 600mm radius curves recommended by the G0G for dock areas, industrial, and factory lines, which are a 88DS' natural environment.