Modelling British outline is a peculiar thing.
There are a number of constraints, historical and practical, which tempt one to compromise.
The first issue is the mismatch between track gauge and scale.
Strictly speaking, Boltorr is being built to a scale of 1:76. More accurately a strange mongrel ratio of 4mm representing 1ft – 12inches. This actually works out to 1:76.2, but this is the least of my compromises.
So, if my layout were built to scale the track gauge would be 18.83mm (4ft 8.5in @4mm/12″), right? Well,wrong. It’s going to be 16.5mm representing 4ft 2.5in. What’s gone wrong?
16.5mm was the de facto gauge for HO models (3.5mm/ft, 1:87), half of O gauge (7.00/ft 1:48 – I know…), the original continental and American compact model standard. 16.5mm is very, very close to being correct gauge for HO/1:87 scale. Unfortunately, when HO first appeared pre-WW2, standard model mechanisms wouldn’t fit in British outline stock because of the comparatively small UK loading gauge, so the larger OO was devised. The downside is that there is a tendency for UK models to look a little narrow gauge on OO track.
So you can see it’s complicated.
However, this iteration of Boltorr is being built in OO gauge. I’ve dabbled with 18.83mm gauge, now known as S4/P4, and it’s possible any follow-up could be built to that standard.
In the meantime, Peco have come to the rescue with their range of finescale bullhead track and points built on the Great Western pattern, which is pretty correct in every respect, other than the gauge. Since I really want something up and running, I’ve settled for that.
There’s a useful review of Peco’s new points here…
Next; laying bullhead track and points, and figuring out how to control Cobalt IP switch motors.