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Sharpest Main Line Curve


D854_Tiger
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  • RMweb Gold

Larpool isn't that tight there is a tighter 25mph curve between Sleights and the site of Eskdale mines box but not as tight as Grosmont. The curve at Battersby is also tight being only 20mph

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My purpose in taking those 5 comparative 6" maps is that those curves were the most quoted mainline curves in the thread.

And of those the Northam curve on the approach to S'hampton Central is surely the most intensively traversed.

 

The old Cromford & High Peak (I am proud to say because our Scout hut was at the bottom of the Shallcross incline) had an extraordinarily tight curve just beyond Parsley Hay i.e. beyond the 'mainline' section that the LNW used for running Euston expresses via Uttoxeter and Stafford to compete with the Midland from Buxton !

According to my measurements Gotham curve was 2.3 chains !

post-21705-0-46641600-1501591747_thumb.jpg

My bet is that most curves RMwebbers nominate are 10 chainers.

Someone mentioned tight curves off the Warrington-Preston section of the LNW.

 

Interestingly I've just looked at the old Grand Junction curves at Earlestown onto the L&M. And guess what?

Joseph Locke was the Engineer for both the LSWR line to Southampton and for the Grand Junction (LNWR) connection between the L&M and the London and Birmingham.

So his Manchester curve at Earlstown is also 7.5 chains, the same as Northam !

 

It has stopped raining now; I'd better go back outside and face the Real world :-(

dh

 

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  • RMweb Gold

How do some of these curves compare with the radius normally used for points.

 

A chain is 66 feet, and a 4mm scalea 2' radius Peco Streamline turnout at 152 scale feet radius equals about 2.5 chains, a lot tighter than the curves quoted at Earlestown and Northam.  These would need to modelled at around 6 and a half feet radius to be in scale, a point to consider when you are reading about the 'massive errors' of the Oxford Dean Goods.

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  • RMweb Gold

The curve at Stourbridge Junction towards Birmingham is 15mph, and there's always plenty of flange squealing to be heard from my grandmothers. I always thought that was really sharp for a mainline.

 

Have you tried oiling your grandmother? 

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  • RMweb Gold

Thinking about Pacers and curves I guess thinking about where they have been banned, like on the Cornish branches, might be a good guide as to severe curves.

 

Or were they banned from Cornwll because of the sheer number of curves rather than the curves being of tight radius.

My understanding was that the issue in Cornwall was a combination of curves and gradients.

 

Pacers (or Skippers as the 142s were called down West) can apparently cope with one or the other but not both together.

 

John

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My understanding was that the issue in Cornwall was a combination of curves and gradients.

 

Pacers (or Skippers as the 142s were called down West) can apparently cope with one or the other but not both together.

 

John

I recall nothing about gradients only excessive wheel wear due to the curves, not helped by monoblock wheel sets!

 

Mark Saunders

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  • RMweb Gold

I recall nothing about gradients only excessive wheel wear due to the curves, not helped by monoblock wheel sets!

 

Mark Saunders

My memory is that there was a braking issue with the Skippers and jokes about the unfortunate accidental choice of name.

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My memory is that there was a braking issue with the Skippers and jokes about the unfortunate accidental choice of name.

No the braking issue was nothing to do with curves it was the Cable Brakes that were the problem but that was changed on all the 14X fleet to the current Direct Acting Brakes which are on them today!

 

Mark Saunders

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  • RMweb Gold

No the braking issue was nothing to do with curves it was the Cable Brakes that were the problem but that was changed on all the 14X fleet to the current Direct Acting Brakes which are on them today!

Mark Saunders

Thanks for update.

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  • RMweb Gold

I recall nothing about gradients only excessive wheel wear due to the curves, not helped by monoblock wheel sets!

 

Mark Saunders

It wasn't unknown for them to slip to a stand going up hill on the steeper curves due to weight transference off the driven wheels.

 

I remember coming up from Falmouth one wet day and thinking the journey would never end!

 

John

Edited by Dunsignalling
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I have a memory of reading in a (possibly unreliable) history that the eastern approach through Sutton Bridge station on the M&GN mainline was the tightest curve on a British mainline, until most M&GN services were ended in the late 1950s. But I have the memory of a fruit fly so may well have misremembered.

 

Paul

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  • RMweb Gold

Local marketing.  The 'Pacer' name was to go with the 150/152 'Sprinter', and when the 4 wheel horrors were first introduced in the South West there were no Sprinters for them to go with, so a different name could be used.

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I have a memory of reading in a (possibly unreliable) history that the eastern approach through Sutton Bridge station on the M&GN mainline was the tightest curve on a British mainline, ...

Doing a PrtScr of the Side by Side National Library of Scotland map of Sutton Bridge the M&GN station curve is to the west of the bridge

I make it to be a reverse curve of 8.5 chains radius.

 

post-21705-0-20244700-1501686296.jpg

Edited by runs as required
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Doing a PrtScr of the Side by Side National Library of Scotland map of Sutton Bridge the M&GN station curve is to the west of the bridge

I make it to be a reverse curve of 8.5 chains radius.

 

attachicon.gifsutton bridge.jpg

Please let me into your secret of how you define the centre-line of the tightest section of a transition curve ??

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  • RMweb Premium

On the London Underground Central Line, the Caxton curve between Shepherd's Bush and White City (westbound) is indicated as 200ft radius (3 chains). With a peak-time service intensity approaching 30 trains per hour every weekday, that's hardly a branch line!

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  • 2 weeks later...

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