Gauge widening in 2mm

[Richard Hall]

Thinking about how to persuade 0-6-0s to go round train set 12" or less curves as I am determined that my next layout will be oval rather than straight... Association standard for gauge widening is 0.10mm maximum which seems to be the prototype dimension scaled down, but looking at the wheel standards and doing a bit of calculation I reckon at least 0.30mm should be possible before the outside of the wheel treads starts to get too close to the edge of the rails.  I've been desperately trying to brush up on school maths, sines and cosines, and think I need 0.40mm for a 9" curve but that assumes a rigid chassis with no sideplay.  So a combination of some sideplay on the centre axle (rear axle driven, and two piece rods) and a big handful of gauge widening should work. Since I'm planning (for now) to stick to 1:148 for loco bodies, splasher clearance should still be OK even with the sideplay.  As usual I'm probably missing something obvious - anyone out there with experience of 2mm FS on very tight curves?

 

Richard

[Kylestrome]

Richard,

 

Chapel Wharf has 12" curves and continuous check rails. At the time of building I knew nothing about gauge widening, so it was all built using the 2mm Scale Association roller gauges. Everything that you would expect to go through such curves has managed with ease, including mainline diesels. The only loco that refused was one of Stephen Harris's scratchbuilt Class 08s which had very little side play.

 

HTH.

[autocoupler942]

Getting the wheels to stay on track is only one issue. Bear in mind body overhang and coupling offset will be gross on 4-wheel stock! Solutions will totally destroy visual pleasure of 2mm.

[Richard Hall]

Getting the wheels to stay on track is only one issue. Bear in mind body overhang and coupling offset will be gross on 4-wheel stock! Solutions will totally destroy visual pleasure of 2mm.

The sharp curves will be totally hidden.  I'm using Micro Trains knuckle couplers at the moment which give nice short distances between vehicles and work fine on 9 inch curves in either direction, even on a Mk1 horsebox which is about the longest four-wheeler I'll need. I've been working on a coupler design of my own but that has stalled for the moment. Don't even mention  B&B / DG couplers, I tried those and have a small pile of things that look like dead houseflies. Can't really see why body overhang will be a problem, it's not like I'm planning to run Gresley Pacifics, although my 4-4-0s might have to do without front footsteps.  My problem is that I live in the world's smallest house, and even if I wanted a terminus/fiddle yard layout (and I don't, been there, done that) I don't have more than a 5 foot straight run anywhere to put it up.  So I'm going with a "squashed oval" version of Ian Futers' legendary circular layout "Longwitton", 4 x 3 and nothing under two foot radius in the visible area. That makes for some very tight curves round the back, and A5 turnouts at best in the fiddle yard.

 

My own view is that the "visual pleasure" of 2mm is much the same as that of N - being able to set your railway within a landscape, even in a very restricted space. Obviously the track looks infinitely better as well, which is important as it is something you see even if there are no trains running. I'm hoping to get smoother running through turnouts from the much tighter wheel and track standards. Correctly positioned footsteps and scale width splashers I can probably live without.

 

Richard

[Nigelcliffe]

........  So I'm going with a "squashed oval" version of Ian Futers' legendary circular layout "Longwitton", 4 x 3 and nothing under two foot radius in the visible area. That makes for some very tight curves round the back, and A5 turnouts at best in the fiddle yard.

"Izzy" who posts here from time to time has built an oval layout for 2mm use which I think is smaller than your proposed 4x3. He lives near Clacton, Essex, so might be in travelling range for you if you wanted to discuss the experiences. His stock is mostly small 0-6-0T and then bogie stock.

 

If Izzy isn't around on the forum at the moment, I can probably make contact.

 

 

- Nigel

[Izzy]

The layout Nigel refers to was called Tendring and on two 54"x 16" boards hinged together, so 4'6" x 2'8" all told. There are a few odd photos of it on this thread; http://www.rmweb.co.uk/community/index.php?/topic/82934-farish-jinty-2fs-dcc/. A squashed oval using a 52" front radius transitioning down to hidden 12" radius at the rear corners and straight along the back. Casettes plugged into both rear sides for stock changing/rotation etc. Being experimental in several aspects, baseboard material (mount board), servo point control, the tight radius, it has now been dismantled and a smaller/lighter replacement, 40"x 33" to better suit my needs and personal circumstances is currently under construction using the lessons gained from the first version

 

The use of diesel era stock meant the tight radius wasn't a critical factor, but even so getting stock to 2FS standards to reliably run on sharp radius track proved a challenge which it is hoped the new version will overcome where it proved problematic at times. There is no doubt long wheelbase and bogie stock doesn't look wonderful traversing such tight curves, so hiding/disguising them somehow is useful.

 

Gauge widened curved track can be produced using the 2mmSA three point track gauge, and with the single leg on the inside, automatic widening relative to the radius results. It is not of course advisable to use the gauge with the single leg on the outside, or gauge narrowing will occur. Done like this at 12" radius the gauge is about 9.6mm. The new version Farish Jinty and 4F I have converted to 2FS to see what kind of track radius they could cope with, (now both converted using the recent 2mmSA conversion parts and wheels - I should really update the thread I started), can just about cope with the 12" gauge widened track.

 

Izzy

[Richard Hall]

The layout Nigel refers to was called Tendring and on two 54"x 16" boards hinged together, so 4'6" x 2'8" all told. There are a few odd photos of it on this thread; http://www.rmweb.co.uk/community/index.php?/topic/82934-farish-jinty-2fs-dcc/. A squashed oval using a 52" front radius transitioning down to hidden 12" radius at the rear corners and straight along the back. Casettes plugged into both rear sides for stock changing/rotation etc. Being experimental in several aspects, baseboard material (mount board), servo point control, the tight radius, it has now been dismantled and a smaller/lighter replacement, 40"x 33" to better suit my needs and personal circumstances is currently under construction using the lessons gained from the first version

 

The use of diesel era stock meant the tight radius wasn't a critical factor, but even so getting stock to 2FS standards to reliably run on sharp radius track proved a challenge which it is hoped the new version will overcome where it proved problematic at times. There is no doubt long wheelbase and bogie stock doesn't look wonderful traversing such tight curves, so hiding/disguising them somehow is useful.

 

Gauge widened curved track can be produced using the 2mmSA three point track gauge, and with the single leg on the inside, automatic widening relative to the radius results. It is not of course advisable to use the gauge with the single leg on the outside, or gauge narrowing will occur. Done like this at 12" radius the gauge is about 9.6mm. The new version Farish Jinty and 4F I have converted to 2FS to see what kind of track radius they could cope with, (now both converted using the recent 2mmSA conversion parts and wheels - I should really update the thread I started), can just about cope with the 12" gauge widened track.

 

Izzy

Thank you very much for that, it is reassuring that someone else has tried this and made it work. Yes, I once managed to get a three point gauge the wrong way round (in EM) and yes, I felt like an idiot.

 

Richard