ge_rik wrote: ↑
Mon Oct 29, 2018 6:42 pm
If i manage to get some definitive answers (positive or negative), I'll post them here.
I know it can be done in the ride-in scales, as we built some many years ago on a 7.25" garden railway and my mate has one on his current 12" gauge line. However locos. weighing 1-2 tons and rolling stock weighing 200-500lbs don't suffer from the scaling issues encountered in smaller scales. Being able to use a steel offcut weighing a couple of kg as the counterweight on the point lever also helps.
We made some that always returned to the same position and had to be manually held over for the other route when making facing moves. These had the lever biased to one side so it worked between about 85deg and 45 deg.
The 7.25" line had a zig-zag to get down the hill from the workshop and those two point levers were arranged differently. When trailed they returned to the direction they had been set for, so the lever worked symmetrically between about +/-40 deg in both directions.
One of the things we found in large scale which may be relevant in garden scale was that the point lever had to work over a fairly small angle, no more than 45 deg from vertical as I remember. We found that if the lever was laid over too far, the smaller wagons tended to climb over the point blades and derail rather than trail through them. The lighter (relatively speaking) weight on the wheels meant the flanges didn't have the leverage to move the point blades if the point lever was laying flat.
I disagree with Peter, most of the variables are maintenance issues and a mathematical model of a model turnout would be a trivial job for the likes of NASA or Boeing. That sort of thing is above my pay grade though......
The Peco over-centre spring for closing the point blades was mentioned earlier in this thread and this design has been used for donkeys years by various manufacturers. Looking at your photo, Piko use it in their turnouts and there may well be one buried in LGB turnouts.
The over-center spring is used in turnouts designed for use with track power and closes the point blades with more force than needed if track power isn't being used. I doubt they can be trailed unless the spring is removed.
My workbench is covered in tools and track support parts and will be for some time, so I'm not going to be doing any work on this until I get some track laid. I look forward to your experience and conclusions though, whatever the result.