Tightest Curve

Main line contender: The Portsmouth curve at Eastleigh. Having gone to college and back every day for 2 years over that section of track, I learnt pretty quickly to always to hold on if I was stood up as even at 10mph, the ride was far from comfortable!

James

 

A & 4½ ??

 

An “A” length switch (the shortest) and an angle through the crossing of 1 in 4.5.

Pointwork is generally described by combination of a series of standard switches (A, B, C etc) and the crossing angle, expressed as 1 in x (6, 7, 8 etc). The lower the switch letter and smaller the crossing angle number, the tighter the effective radius through the point. I seem to recall that when the point at the north end of Sheffield Park was relaid some years ago, it was an E10.

Tom

 

Thanks guys - this was weirdly vague I know! Had been thinking about some of the model railway curves you see and wondered what the tightest curves really were out there

 

As Tom says, the letter and number refer to the switches and crossings used in building up a turnout (never points!) The sharpest simple turnout generally found on the big railway these days is a B & 7½. The sharpest natural turnout (where the switch radius and turnout radius are the same) is a B & 8, which has a radius of 613 feet, except on the GW, where it was 603 feet. As the original poster made reference to model railway curves, a B & 8 is 65ft-1½" from switch to crossing nose so, in 4mm scale that would be a bit over 10" long. The sharpest curve without a checkrail is generally 10 chains which, in 4mm scale is 8'-8" radius.

 

Following on from my post I do believe Gotham curve was at one point the sharpest standard gauge curve on the network, it did in fact class as a main line at one point as well I believe, i don't know when it was the sharpest curve owing to it having been open as far back as the 1830's, the curve was 80 degrees over 2 1/2 chains the reason it was so sharp being the line was built to canal engineering standards following the landscape contours, so there are some very odd bits to be seen. Rails on the curve often were blown out and from photos there was always a pile of chairs on standby for repairs. But of course if industrial railways and sidings are allowed there are other far sharper contenders.

 

How does the approach to Carnforth station from the Wennington direction compare? The Pacers seem to squeal loudly there and I think it is 10mph.

 

There are some pretty ferocious curves and indeed steep gradients between Calstock and Gunnislake (it was built as a narrow gauge line).

 

A couple of pictures of Gotham curve in 1964, it was the only place on BR where the J94 locos had to have oval buffers fitted to counter buffer locking problems.

 

Hunsbury Hill on a photo charter a few years ago. Loco and two wagons. The second wagon is at pretty much 45 degrees to the loco! Nice bend in the track just before the crossing too.

 

That's incredible, thanks!

 

Hi Dan,
I was always under the impression that the sharpest curve on LU (but probably meaning on a passenger line) was on the Central Line somewhere around Wood Lane / White City. What's the radius of that bit? I believe it was due to the fact that Wood Lane (now closed) was the original terminus and when they extended the line they decided to set off in a different direction.

Honourable mention to the platforms at Bank on the Central Line too. What radius are the curves there?

 

Deleted

 

I take it the first shot is of the new Northern stock

 

I don't know what radius those curves are, although I believe they are the tightest on the passenger carrying bits of LU. The 46m curve is laid down in our standards as the tightest we have. Will do a bit of digging and see if I can find out more!

Regards,

Dan