7mm Radius curves

[Penrice09]

Does anyone else use 6" and 8" radius curves on their layout, most of the curve would be hidden and 0-4-0 locos and 4 wheel stock?

[sir douglas]

its possible to use 2ft radius curves with only 4 wheel stock

[alfsboy]

My experimental uses 6 inch radius curves .It takes the Bachmann spectrum  0-6-0 saddletank and gas mechanical ok .Four wheel wagons work fine  as do 8 wheelers.I tried uK 4 mm stock and the 4 wheel wagons are fine but a loco like a Terrier has too long a wheelbase.Both the uK type coupling and US style knuckle like KD's worked well.

[decauville1126]

I've just done 3.5 inch radius and pointwork in 4mm scale as an idiotic experiment. Might try tighter next time. If you don't try what you're thinking about you'll never find out.

[sir douglas]

ive done 74mm radius curve In 7mm scale , trying to model Hudson track, set in an average back garden

 

http://www.rmweb.co.uk/community/index.php?/blog/1150-a-back-garden-railway/

 

after over a year, it still isn't fiished

[bécasse]

To give a prototype comparison, the tightest Hudson 2 foot gauge portable track intended for loco use was 36 feet radius (measured to the centre line, it's often quoted as 37 feet as measured to the running edge of the outer rail) which is 252 mm or 10 inches in 7mm scale; this was really only suitable for small 4 wheel locos.

 

Hudson's also produced curved portable track set to 12 feet 3 inches radius (to centreline) but that was only intended for use in situations where a single wagon is pushed by hand.

 

Using suitable locos and rolling stock, it is, of course, possible to use curves tighter than those used on the prototype and some very successful exhibition layouts exist. However, even using the prototype's 36 feet radius, it is pretty much essential to avoid the use of reverse curves - always insert a straight section at least a wagon length long between curves of opposing hand.

 

It is a useful rule of thumb to say that track minimum radii and gauge will be in inverse proportion to each other.

[Shannow]

Hello,

 

I'm very new and thinking of track layouts for O-16.5mm but I can't find anywhere information (especially as I live in France) as to how tight curves can be for a layout in this scale.

I was wondering can something gigantic like a NGG16 Garratt go round 15" curves ? Or perhaps tighter ? Although I'm feeling 15" is pushing my luck...

at the moment most of what will go on this layout will be EDM models and DIY bogie coaches.

 

Sorry if I bumped in this topic and shouldn't.

 

Thank you very much in advance

 

Jonathan

[bécasse]

In France during WWI, on the military 60 cm lines, the minimum radius track intended for use by steam locomotives was 20 metres, although 30 metres was preferred.

 

In 7mm / 1/4inch scale, 20 metres equates to around 18 inches, although that is for 60 cm gauge not 75 cm (= 30 inches). Given that models will generally happily traverse tighter curves than their prototype equivalent would, you might just get away with 15 inches, but 18 inches would be better, and 27 inches (~ 30 metres) very much better.

 

A lot will depend on how long the overhangs outside the wheelbase are, and how consistent they are between locos and rolling stock, as the ability to remain coupled is often more of a limitation than the actual ability to go round a curve.

[Shannow]

Thank you very much for your reply. Did narrow gauge railways use easement for curves ?

I'm ironically much more interested in English locomotives/railway than French so I'll try to imitate something like the Ffestiniog railway . Unfortunately I only have something like 4ft x 6ft 1/2  space maximum.