I'm intending to build a layout with standard and narrow gauge scenarios but would like to know what is the smallest radius curve available in 009?
https://www.trainshop.co.uk/oo9/19950-festiniog-prince-loco-oo-oo9-scale-1-76th.html (https://scontent-lhr3-1.xx.fbcdn.net/v/t1.0-9/63081785_2557021764349094_782535224490721280_o.jpg?_nc_cat=101&_nc_eui2=AeGbiAZthlAujRD21mVx_obvM3hnDMsn8RtuDRqUP3_g-6TBfs_9kE4hvb0BjUXAo7qteM5HOmWkKfjaA9F9jzad5r6bnwYkautQbHYMGaJVnw&_nc_ht=scontent-lhr3-1.xx&oh=67e1223f81c56dbb44eea8bdfc808976&oe=5D7E977C)
Also, I'm looking at building this but it needs "upgrades" to complete form someone here.https://www.trainshop.co.uk/oo9/19950-festiniog-prince-loco-oo-oo9-scale-1-76th.html
Good - you've made a new topic! (so I have copied my reply to here...)
Welcome to the forum.
Oh dear... Is that the sound a tin of worms being opened?
Don't get disheartened by the answers / comments you may receive! It is a thorny issue and usually generates a lot of debate.
To kick off the debate I have 9 inch radius curves on my layout and have no problems with any of my existing loco fleet (which includes a 0-8-8-0 mallet).
It depends on what you intend to run and whether it will look "realistic" running on your track; basically you would not expect to see big locos running round tight curves!
It also depends on what you intend to do; shunting may prove problematic round tight curves.
P.S. Try to visit shows that have 009 content and chat with the operators; they are a friendly bunch and happy talk about the hobby and answer your questions. Also, see if there is a nearby group of the 009 Society and get along if you can. Nothing beats meeting face to face.
I aquired a layout (Thurtey) that has curves down to about 5" radius.
Small locos will manage them ok but the stock needs to be small other wise the couplings can pull them off.
I'm using the Society open wagons, Peco vans and Peco 4 wheel GVT coaches etc
My other layout uses the Peco 9" radius curves and I don't have any problems with larger locos on stock on them
As Hugh says there
It will not be the wheelbase of the locos and rolling stock that will give you problems on tight curves it will be the couplings.
Basically, the tighter the curve the more work will be needed to get the couplings round the curves without de-railing the stock.
I have 9-inch curves on one of my layouts and this does restrict the things I can run on it, not just because the larger items will look daft, but mainly because of the coupling overhangs.
Making the couplings pivot can work, but unless that self-centralise coupling up will be a pain and when propelling the couplings may well lock up.
Then there is the subject of reverse curves. (Points on crossovers for example) With these the coupling overhang is twice that of a normal curve of the same radius.
So, it ends up as a compromise the tighter the curves the more problems you will have and the less items you can run. The larger the curves the less you can fit in the space you have.
A couple of examples of how the curves on actual railways work out in 00 scale are the FH/WHR at 22-inch radius in 009 and the Talyllyn at 53-inch radius in 009. (The TR has side buffers that require a bigger radius to stop them locking up.) So anything you go for will be far tighter radius than these lines use.
Brian Meldon
Thanks all. Much appreciated.
Another point which is so obvious to the experienced members who've already replied that they've forgotten to mention it is that you can't get away with as tight a radius on reverse curves. eg small stock can happily go round a 150mm radius Unitrack N as long as it's only curving in one direction.
Quote from: S Arrowsmith on June 13, 2019, 16:41
Another point which is so obvious to the experienced members who've already replied that they've forgotten to mention it is that you can't get away with as tight a radius on reverse curves. eg small stock can happily go round a 150mm radius Unitrack N as long as it's only curving in one direction.
Thanks. Never thought about that.
Quote from: S Arrowsmith on June 13, 2019, 16:41
Another point which is so obvious to the experienced members who've already replied that they've forgotten to mention it is that you can't get away with as tight a radius on reverse curves. eg small stock can happily go round a 150mm radius Unitrack N as long as it's only curving in one direction.
That is what I said regarding couplings.
Quote from: B.Meldon on June 13, 2019, 11:41
..........Then there is the subject of reverse curves. (Points on crossovers for example) With these the coupling overhang is twice that of a normal curve of the same radius.....
Brian Meldon
The smallest radius technically possible is about 20mm; - but as set out above, for single vehicles only. Is it prototypical? Yes, on tub-runs in some mines they use 'turntables', i.e. motorised disks with railings around them, behind the tumblers to turn the tubs and send them back to the shaft. ;D
But unfortunately you do not mention, what prototype you want to model (industrial narrow gauge, public common carrier, ...); - or what stock has to traverse that curve?
If you run Eggerbahn, Jouef/ Playcraft), ROCO, or Minitrains industrial (2-axle) vehicles only you can go down to about 120mm radius, slightly less building your own track with appropriate gauge widening. As explained by others, this is likely to require modifications to couplings for whole trains not to derail!
If you plan to run 3-, 4-, and 5-axle engines, e.g. Bemo, Weinert, Ferrotrain etc. you should aim for 400mm or bigger. The Bemo 3-axle (Wuerttemberg-) stock does do 280mm on a pinch, but a minimum of 340mm is recommended to ensure accident-free running.
Food for thought: Minitrains, like Eggerbahn and Jouef, offers set track with 140mm, but expressly states that engines like the Brigadelok are likely to cause derailments.
Bear in mind that the tighter the radius, the more likely the wagons will derail as the couplings' pull into the curve increases; that might very well limit train length.
As always, I recommend sticking with tried and tested standards, e.g. Fremo (who specify 340mm minimum).
Cheers
Waldschrat
Quote from: B.Meldon on June 14, 2019, 13:54
Quote from: S Arrowsmith on June 13, 2019, 16:41
Another point which is so obvious to the experienced members who've already replied that they've forgotten to mention it is that you can't get away with as tight a radius on reverse curves. eg small stock can happily go round a 150mm radius Unitrack N as long as it's only curving in one direction.
That is what I said regarding couplings.
So you did. My apologies.