What is a small radius curve?

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LocoLyn

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Could someone please explain (in layman's terms) what a 'small Radio curve' is? ref greace being automatically sprayed onto both wheels of the first axel.

I'm currently reading about pneumatic systems and what I can gather is that the the pneumatic system aids the horn coupling, drivers seat etc. But I don't have a clue what a radio curve is.

Hope you can help as I've searched the Web to no avail.

Lyn
 
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Domh245

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I think it may be radius rather than radio. In essence, tight curves (hence the application of grease)
 

LocoLyn

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Ah, thank you Dom, maybe it's a typing error in the file I have.

Now that makes more sense to apply grease to help with the wear and tear on the wheels as they enter a curve.
 

LocoLyn

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Aww thank you Edwin, I'll nip there now and have a read, much appreciated :)


Thank you Edwin, this is was so easy to understand, the new 777 Merseyrail trains have an on board spray system and I also watched the video too,

"On-board Lubrication Systems

This systems for wheel flange lubrication and railhead conditioning are mounted on-board on the first leading vehicle axle."
 
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Train jaune

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They need some grease when I head out of Carnforth heading towards Skipton. It's worse than the fingernails down the blackboard.
 

Titfield

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Pre formed track for model railways typically comes in three radii. Small radius, standard radius and large radius.

The smaller the radius the tighter the curve. The tighter the curve the more you get flange wear.
 

edwin_m

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Pre formed track for model railways typically comes in three radii. Small radius, standard radius and large radius.

The smaller the radius the tighter the curve. The tighter the curve the more you get flange wear.
And all radii on model railways are way tighter than a scaled-down version of what you'd get on a real one, except on tramways or something like Docklands Light Railway. According to a quick search, the largest radius in 00 gauge non-flexible track is 572mm, which scales to 43 metres. Virtually no heavy rail rolling stock would go round this curve without derailing. For context, a curve with a radius of a mile would typically have a maximum speed of around 60mph.
 

Ploughman

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Sub 200m radius will need to be fitted with Check rails.
They will also have a low speed imposed, probably around 20 mph as at Crimple curve near Harrogate.
I don't think that there are many curves on passenger lines below 150m rad but I will be proved wrong.
 

LocoLyn

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Thank you all so much for your input.

I'll probably be asking more questions on different stuff about different components to do with the Woking of trains, as when I search on the Web I always get the long winded answer and a lot of the time it goes over my head ha ha when it could probably be answered in one sentence by one of you lovely people.

Thanks again ... Lyn
 

Annetts key

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In the area where I am, the tightest curve for a ‘main line’ passenger line that I’m aware of is the “Rhubarb Loop”, officially called the Bristol Loop Line. It’s a short two track railway linking Dr Day’s Junction and Feeder Bridge Junction/North Somerset Junction.

ELR is BLL
Sectional Appendix LOR GW530

The line speed is 10MPH and it experiences a high rate of rail side wear.

This site has some photos.

There are tight curves elsewhere such as on freight only lines, sidings and on single lines.
 

LiftFan

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In the area where I am, the tightest curve for a ‘main line’ passenger line that I’m aware of is the “Rhubarb Loop”, officially called the Bristol Loop Line. It’s a short two track railway linking Dr Day’s Junction and Feeder Bridge Junction/North Somerset Junction.

ELR is BLL
Sectional Appendix LOR GW530

The line speed is 10MPH and it experiences a high rate of rail side wear.

This site has some photos.

There are tight curves elsewhere such as on freight only lines, sidings and on single lines.
It's a similar situation with the Westbury East curve, it's rare to get passenger trains but I have ridden some during short notice diversions.
 

Gloster

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It's a similar situation with the Westbury East curve, it's rare to get passenger trains but I have ridden some during short notice diversions.
Indeed, but it used to see scheduled diversions, even though it meant finding a signalman for Hawkeridge Junction box. I once went that way on a Sunday morning on the Up Fishguard: all the way to Reading to get a train back to Exeter.
 

AM9

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The tightest mainline curve radius on the LU system is I believe 5 chains*. It's just east of South Kensigton station.

*5ch is just over 100m
 

AlbertBeale

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The tightest mainline curve radius on the LU system is I believe 5 chains*. It's just east of South Kensigton station.

*5ch is just over 100m

Is that really tighter than where the westbound Central wiggles round after leaving Shepherds Bush?? The latter always feels tighter than the Picc at South Ken.
 

Recessio

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The DLR has some particularly tight curves too, but can't find figures to hand. Iirc the wheels are more conical than other stock to deal with this, but that's why the units have the unusual side-to-side oscillations you don't to get on standard stock.
 

AM9

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The DLR has some particularly tight curves too, but can't find figures to hand. Iirc the wheels are more conical than other stock to deal with this, but that's why the units have the unusual side-to-side oscillations you don't to get on standard stock.
The DLR had wheel and track standards more akin to tramways than a heavy rail system.

Is that really tighter than where the westbound Central wiggles round after leaving Shepherds Bush?? The latter always feels tighter than the Picc at South Ken.
I remember way back in an article in the London Transport magazine on the plans for the Victoria line where it referenced the problems of running the Piccadilly trains through those 5ch. reverse curves Vs the ruling minimum planned for the Victoria of 20 ch. Maybe the Central line alignment at Shepherds Bush wasn't considered to be as operationally significant as those at South Kensington.
 
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