Hi Martin,
It's good to have the clarification of your intension. I read your previous post as minded, meaning your still thinking about it. Which I understand as there are some complications to overcome.
Which means to create complex formations such as tandem turnouts, outside slips, double junctions, etc., it is important that the rail can be assembled into the track base vertically from above.
Your comment about vertically from above, can be achieve in one of two ways.
You can either have a two part chair, where the base can be inserted as a plug, which to all intents and purposes you build the timber and chair base as a pre assembly then drop the rail in vertically and attach everything together using the loose jaws. (which is a genius concept by the way)
If your modelling in 4 mm or above that scale, I 100% agree with you, where its possible to drop the rail in vertically and then add the loose jaws it solves a series of other issues.
The other option which was the logical evolution of plug track, is you have a one piece chair which slides onto the rail, thus building a rail length (long or short) with the right chairs, pre slid onto the rail.
This subassembly is then pushed down vertically into the sockets provided in the sleeper/timbers.
There are some limitations to this plug in approach, which I would say require more care and even pressure needing to be applied to the chairs to allow them to push into the sockets without at the same time breaking the chair on the rail. certainly doable though.
If your in 2mm and maybe 3 mm I am not sure the loose jaw option is a practical proposition. I am not even sure one piece plug chairs will totally work in 2 mm scale. ( no harm in trying though) for 3 mm plug chairs are viable and maybe even loose jaws are as well!
It must be said though, that other methods are avaible, there is the slide the chairs on the rails and then glue the chairs down. Not strictly plug track, but possibly an option for the aforementioned complex formations!
Or you can go for the slide chairs on rail as far as practical, using a slid the chairs down more than one piece of rail then press the sub assembly home and then join the rails approach.
So such thing as prototypical one piece bent Knuckle will have to be sacrificed for a non prototypical joint at the knuckle. The idea is certainly not new, with other track building options on the market, already using this approach.
Therefore if you follow the logic, you would have to conclude, that certainly for 2mm and maybe even 3 or 4 mm scale FB projects. Other means of creating as realistic a track representation as possible will need to be explored.
I do agree that when it comes to Pandrol clips, even in O gauge there unlikely to be realistic and still work. The smaller the scale the more deviation for the prototype will likely be needed.
In conclusion FB rail clamping options will be harder to accurately model, when compared to BH, but that should not rule out quite a few options that can be explored by others going forward.
cheers
Phil,