Trivia: Curviest Circle Line

[Peter0124]

Hi, I am wanting to work out what the curviest (or sharpest) Circle or loop line is. They would likely be the smallest in size as the curves to join the circle would be significantly tighter.

The Cathcart Circle isn't that long and has some very sharp curves connecting it.

Any ideas of more Circle lines that are quite small (in diameter or track miles) or notably curvy? It can be anywhere in the UK, or abroad etc.

 

[McRhu]

Smallest radius? One of the narrow gauge lines. (Are we including narrow gauge?)

 

[zwk500]

Not always though of or called a loop, but the rounded square formed by Newcastle station, the High Level & King Edward Bridges and the Gateshead link line is c.614m wide between the inner tracks of the bridges, and about 680m between the inner tracks of the sides parallel to the Tyne.

 

[swt_passenger]

Not always though of or called a loop, but the rounded square formed by Newcastle station, the High Level & King Edward Bridges and the Gateshead link line is c.614m wide between the inner tracks of the bridges, and about 680m between the inner tracks of the sides parallel to the Tyne.

I’ll just go and think of another one… Grrrr.

But does there have to be stations on the circle?

 

[Railsigns]

The circle at Radlett is quite small.

 

[zwk500]

I’ll just go and think of another one… Grrrr.

But does there have to be stations on the circle?

There's also a historic mention to the historic curve that allow trains to Run London-Trent-Derby without reversal, which appears to have been c.750m wide.

 

[tbtc]

I wonder if a colliery or other industrial land might be the winner (at least historically, since there are fewer examples nowadays), given things like the Merry Go Round concept, but I guess this would be on private tracks so might not meet with everyone’s definitions

For example, West Burton A Power Station off the (Sheffield) Retford - Gainsborough (Lincoln) line:

https://maps.app.goo.gl/gC88EuW23iWTUd749?g_st=ic

 

[30907]

The Cathcart Circle isn't circular, and Langside to Queens Park looks to be at least 1.25miles, which zwk500 has comfortably beaten.

There are two circular test circuits in mainland Europe - Velim in CZ looks to be about 1km across, while Wildenrath in DE is about 800m. Of course, those are designed for testing trains at speed so don't represent a minimum!

The Dduallt spiral on the Festiniog probably beats the lot, but it isn't a circle - the same would apply to umpteen spirals in the Alps and elsewhere.

PS ISTR there has been a thread on the smallest radius curves, and P5 at Shipley would be among them.

 

[MarkyT]

The circle at Radlett is quite small.

A bit egg-shaped, measuring approx. 120m radius at its tightest.

 

[zwk500]

One interesting one is in Birmingham, where from New Street to Perry Barr jns via Aston it's an almost perfect continuous radius, but then from Perry Barr back via Soho Jns to New Street it gets very wiggly indeed! Sadly it's far from the smallest on the network.

 

[Peter0124]

The Cathcart Circle isn't circular, and Langside to Queens Park looks to be at least 1.25miles, which zwk500 has comfortably beaten.

It doesn't have to be a perfect circle! But yes

 

[Magdalia]

The Ely West Curve is exactly a mile long. The direct route from Ely North Junction to Ely West Junction is 56 chains, so the whole length of the loop is 1 mile and 56 chains. The southern end of the loop is semi-circular with radius of about 200m/10 chains.

 

[Dr Hoo]

For standard gauge, in a public area, I would have thought that the Blackpool Tramway loops at Pleasure Beach and Little Bispham were in with a shout.

 

[RobertsN]

Scarborough North Bay railway has a teardrop with an approximate side-to-side of around 18 metres (so basically a 9-metre radius - give or take a bit).

OK, turning tongue-in-cheek off... Will grab my coat and hat.

 

[Basil Jet]

The circle at Radlett is quite small.

Nice! I was going to suggest the one a little south of Bicester Village, but Radlett is much smaller.

 

[matchmaker]

Glasgow Subway?

 

[route101]

Hi, I am wanting to work out what the curviest (or sharpest) Circle or loop line is. They would likely be the smallest in size as the curves to join the circle would be significantly tighter.

The Cathcart Circle isn't that long and has some very sharp curves connecting it.

Any ideas of more Circle lines that are quite small (in diameter or track miles) or notably curvy? It can be anywhere in the UK, or abroad etc.

I'm surprised the sleeper and Pendolino's are cleared for the section through Crosshill.

 

[Peter0124]

I'm surprised the sleeper and Pendolino's are cleared for the section through Crosshill.

Yes, I'm surprised they aren't cleared via Maxwell Park which is much gentler.

 

[MotCO]

Does the Tramlink circle round the centre of Croydon count?

 

[Springs Branch]

How about Merseyrail's Wirral Line loop beneath central Liverpool?

The Wirral Line isn't a smooth loop. There are some straight-ish sections (e.g. at Lime St & Central stations) with tight, squealy curves in between, which are notoriously aggressive for wheel flange and track wear.

The design radius curve on the loop is 210m*. I'm not sure how this figure stacks up against the other contenders.

* Source is paragraph 25 on page 10 of this link.


[EDIT] I've seen mention on another forum that the Kennington Loop on the London Underground has a radius of 75m and a 15 mph speed restriction.

Could this be the sharpest curve balloon loop on a standard gauge, passenger-carrying system (which isn't a tramway or light rail)? Although one that’s difficult to appreciate, being totally underground and not officially available for travel by ‘normal’ passengers.

Note that Kennington is not the sharpest curve on the Underground system, but it is the one which 'loops' the train the full 180°.