I was considering the purchase of a Heljan 2-4-2 Baldwin and contacted Hattons to confirm details regarding necessary radius. When I stated I used Peco SLE 491/492 points, I was told these would be too tight for the engine. I thought these points were used by many modellers so would cope with most engines, rookie error perhaps! 🙈 My sharpest curve on my layout is 25cm radius.
If anyone has one of these engines and can share their experience. it would be much appreciated, I may just have to build a branch line if I wish to run one of these engines!
Thanks
Peter
Hi Peter, I don't have one of these locos, but, I scratched built one, and although it would go around my layout curve the rear bogie would pop off the track. After much scratching of my head I figured that the lenght of my chassis was greater then the radius of the curve. The only way for my loco to go around would be to have the rear bogie swivel as well as slide in its mounting.
I have a couple of these peco points on my layout and have no problems running my locos through them. As long as there is ample swivel in the front and rear sets of wheels.
All my locos and rolling stock wheels are set to the NMRA gauge.
I know this not quite the answer you were looking for, but some one else might pick up from here and shed more light.
Robin.
There is a bit more to it than just the radius. The Peco SLE 491/492 points were updated in 2010. You may well find problems with the ones made before 2010. The later ones have far better geometry, a more constant curve, longer check rails and the straight is actually stright! (They previoulsy had straights that were curved, check rails that were too short and the curve was effectively two straights with a curve in the middle.)
The way to spot the old ones is that they had a fishplate piviot for the moving blades. The later ones have a proper piviot for the blades.
I also tend to always avoid reverse curves when planning layouts, in general 12 inch revers curves can casue some issues with couplings, but 18 inch reverse curves are in general OK. (Peco 009 Y points and mainline points are 18 inch radius.)
To look at the issue another way Peter...
The SLE 491/492 points have a radius of 304mm, which if we scale that up to full size would be 76 feet or about 25 yards, and the 25 cm radius curves equate to 62' 6" or just over 20 yards.
Whilst most of the small 'industrial' locos beloved of 009 modellers - Quarry Hunslets and the like - would experience such curves in real life the 'common carrier' lines would not build such tight curves. The Wikepedia entry for the L&B (https://en.wikipedia.org/wiki/Lynton_and_Barnstaple_Railway) would suggest the minimum radius on curves was 5-chain, or 330 feet, or for a 4mm scale 009 model 132cm - a little over 4 feet!
Looking at it that way Heljan have done well to design a model with a suggested minimum radius of 305 mm ( one foot).
It might be possible to modify the Heljan loco to increase the swing on the pony trucks to enable it to get round the curves on your layout, but it's quite understandable that you may not want to mess about with such an expensive bit of kit, especially as doing so could invalidate any warranty on the loco.
In that case it will probably be easier to look at redesigning the layout, sorry.
(* Terms like 'small' or 'large' are, of course, relative. If one's own passion is things like South African NG Garratts and other 'colonial' NG then the L&B Baldwin starts to look a bit on the small size!).