Sensible minimum radii for reliable continuous running

flexible_coupling

flexible_coupling

Western Thunderer
Scale7JB said:
Another thing to consider is a continuous check rail, this will allow for tighter radii, and looks the part on tight curves too..

JB.
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I quite like the idea of using check rails prototypically in that fashion, and plan to use this with some of those cool gauge-widened 'check rail chairs' from whatshisname via shapeways. The pic towards the over-bridge leading away from the loco shed at Mountain Ash (as per the photo linked just below) is something I'm aiming to represent; the track verging to the left will be essentially "curving around" to form the left-hand 180-degree curve of the oval.

https://flic.kr/p/9P3iHe

The photos of the area suggest that it's really quite tight, alleviating my conscience a little! I'll have to fiddle and play a bit with it all with some test laid track to get the right combo of gauge widening/check rail clearance etc... might end up nudging the 57xx build to the head of the pile as it's liable to be the largest "affected" loco.
 
BrushType4

BrushType4

Western Thunderer
Great picture. Will you be modelling the section of bypass track over the weighbridge? I pretty sure that will be a modelling first. :thumbs:
 
flexible_coupling

flexible_coupling

Western Thunderer
BrushType4 said:
Great picture. Will you be modelling the section of bypass track over the weighbridge? I pretty sure that will be a modelling first. :thumbs:
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Oh definitely! I do look forward to replicating that. In the 1960-ish to 1980-ish timeframe I'm keen on working with, the loco shed (and yard behind), weighbridge and the 'diverging' under the over-bridge are the primary points of interest. The bumpy track is also a factor! I'll have to compress it length-wise but I fancy I should be able to get a comfortable-looking rendition of that stretch - I'm hoping to be able to afford about 12-14' of length on the 'straight'. I'm comfortable with "not" doing the south-side of the canal with the wagon-shop etc., I'll use the canal as my board-edge. I can't seem to find again the excellent quality 1950's ordnance map I found online some time ago.... more hunting!
 
flexible_coupling

flexible_coupling

Western Thunderer
ZiderHead said:
Try http://maps.nls.uk/geo/find/index.cfm :)
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That's the one!! So hard to 'win' at Google sometimes. The 1952 map gives a fair overview of what's "going on" but there's a few things that are and aren't there 20 years later!

Scaled it up.... the afore-mentioned track deviating off to the left under the road bridge, crossing the canal, scales to about 6'9" radius in 1:43.5. That's straight off the map! While running the rule over things, I need about thirty feet to cover my intended scope of operation where I have about 10-14 (at a pinch) to play with! So a lot of things will have to shuffle around.... all part of the fun!
 
flexible_coupling

flexible_coupling

Western Thunderer
ZiderHead said:
No kidding! The entire course of the river was moved over to where the colliery sidings were when it was decommissioned and the A4059 New Rd built, whenever that was :eek:
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Unless I'm completely mad - I can't see an outrageous amount of deviation for both river and the "new road" between the two similarly-scaled-and-placed maps - certainly everything "north" of the new road has changed drastically in terms of the residential section!
Old 1952 map (you'll have to zoom in);
http://maps.nls.uk/view/102182964
and new Google Map;
https://www.google.com.au/maps/plac...2!3m1!1s0x486e17e206231bd1:0x5c4686859368b6e4

If those links don't work, then I've failed completely at the internet tonight!!
 
ZiderHead

ZiderHead

Western Thunderer
If you look at the old map, the river passes under the bridge then veers N until it gets close to halfway along Dyffryn Rd, then veers hard W again between the colliery and its sidings. It now cuts the corner completely and just runs alongside the Aberdare branch line. The residential area hasn't changed much at all since 1948, just one new road with ~25 houses (Trem Y Dyffryn) on the site of the old lime kilns.

The links worked - internet win! :D
 
richard carr

richard carr

Western Thunderer
I have got my JLTRT 40s to go round 6 foot radius curves but I had to design a new bogie chassis to permit this,.

So so long as you build locos bearing in mind the tight radius I think you will be be fine with Bo Bo locos and small 0-6-0s. You will find that check rails are very effective, you will probably want the whole radius with one, I have them on some 8 foot radius curves and they work.

Richard
 
flexible_coupling

flexible_coupling

Western Thunderer
ZiderHead said:
If you look at the old map, the river passes under the bridge then veers N until it gets close to halfway along Dyffryn Rd, then veers hard W again between the colliery and its sidings. It now cuts the corner completely and just runs alongside the Aberdare branch line. The residential area hasn't changed much at all since 1948, just one new road with ~25 houses (Trem Y Dyffryn) on the site of the old lime kilns.

The links worked - internet win! :D
Click to expand...


After looking at the photos Osgood referred to in another thread, I cottoned-on to the part of the river that had significantly altered (I was looking at the wrong part!).

Sadly, those photos are a little early for my time-line.... as best as I can figure out, the weighbridge was "plonked" on the former Cardiff Road-station alignment at some time between the original station closing in 1964 (according to Wikipedia) and photos I've seen from about 1975 - guessing earlier rather than later. That having been said... perhaps a little Rule #1 can be applied. I had mused over the idea of trying to stretch my time-frames out from being fairly exclusively set between 1975 and 1980 to potentially trying to cover 1960(ish)-1980. The "late" time-frame rules out anything much other than colliery operation, not that there's anything wrong with that. A re-imagining of the line where the station wasn't actually closed to passenger traffic would be very interesting to me! Perhaps the line through was rationalized to single track running that tucked around the back of the weighbridge building that was built up, then under the bridge (heading north) and out of view. I shall give this idea some further thought............
 
flexible_coupling

flexible_coupling

Western Thunderer
I had a bit of a flickr binge today, and am placing these image links largely for my own later reference, but they seem to show the progression of removal of the Cardiff Rd station at Mountain Ash... and give me some ideas as to how I might "un-make" that progress....

https://www.flickr.com/photos/irishswissernie/5765290884
https://www.flickr.com/photos/irishswissernie/5764740743
https://www.flickr.com/photos/52150321@N02/6807584150
https://www.flickr.com/photos/irishswissernie/5765284156

It's an interesting transition.

Then other angles that I hadn't seen before....
https://www.flickr.com/photos/irishswissernie/5764737251
https://www.flickr.com/photos/glevumblues/8630932729
https://www.flickr.com/photos/goremirebob/8315163528
https://www.flickr.com/photos/69947186@N08/6648537053
https://www.flickr.com/photos/irishswissernie/5765271858
 
R

rusty

Active Member
Just joined WT so my input is a bit late but I have built, or helped to build, three S7 roundy layouts all of which operated with six coupled tank and tender locos. The minimum radius was 5' 6" in the storage loops and 6' 6" on the scenic bits. I used gauge widening and loco frames set at approx. 28mm (outside measurement) to allow for some 'drift' on the centre axles - this worked well but any points on the curve were avoided so far as possible with check rails used extensively when I had to build a curved point.

Worth noting that a GW 57XX class 0-6-0T has a fixed wheelbase of 15' 6" compared with 16' 0" under a 28XX 2-8-0 and my model versions are both able to manage tight curves. The locos that have given me most problems are larger tank locos with a radial axle on a rear uncoupled wheelset eg large 61xx 2-6-2T. I have no experience of operating 'modern' diesel locos.

To revert to your question, to be honest, I doubt if you could get six coupled S7 locos to work on a 4' 6" curve - four coupled industrial locos might manage the challenge though. Good luck and I hope I am wrong!

Julian
 
DavidinAus

DavidinAus

Western Thunderer
I've been reading this with interest. I have a "round-roundy" with 2 metre (6'6") radius curves and don't have trouble with my engines - although if you want a large steam industrial prototype to go around tight curves an 0-4-0+0-4-0 Garratt is hard to beat. However my six-wheel non-powered stock with S7 wheels has to have a lot of weight on it in order to stop is riding up over the curves. Meaning 200g on my 6-wheel L&Y flat wagon, hidden in the load of girders:

Small L and Y 6 wheel flat wagon.jpg

Weight helps!

David
 
flexible_coupling

flexible_coupling

Western Thunderer
Having made my move of house and run a tape over the available space in the garage... I'm at the stage of serious reconsideration on roundy roundy status. I have about ten feet of width, which pushes me closer to 4' continuous radius. Not ideal.

I do have about 40 feet of length though!! A pleasant development. If it can't be circular, it'll at least have a fair amount of clear running space.....
 
JimG

JimG

Western Thunderer
flexible_coupling said:
Having made my move of house and run a tape over the available space in the garage... I'm at the stage of serious reconsideration on roundy roundy status. I have about ten feet of width, which pushes me closer to 4' continuous radius. Not ideal.

I do have about 40 feet of length though!! A pleasant development. If it can't be circular, it'll at least have a fair amount of clear running space.....
Click to expand...

Is it possible to look at having a form of dumb-bell layout with, say, six foot radius curves at the ends and the curves exiting through the garage wall onto a two or three foot wide shelf, then turning back through the wall to give about twenty foot of length inside for something like hidden sidings. I dare say it depends on what's outside the garage. :)

Jim.
 
flexible_coupling

flexible_coupling

Western Thunderer
JimG said:
Is it possible to look at having a form of dumb-bell layout with, say, six foot radius curves at the ends and the curves exiting through the garage wall onto a two or three foot wide shelf, then turning back through the wall to give about twenty foot of length inside for something like hidden sidings. I dare say it depends on what's outside the garage. :)

Jim.
Click to expand...


Next door's garage is on the other side of the garage wall! I've got a single unit and the garage is below. I fancy end-to-end is the likely culprit with train turntables at each end and a hidden run-around siding at the back to simulate continuous running. Idea plucked out of an exhausted-from-moving-house brain...
 
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