Check Rails on Curves

[DCB]

I am not sure cosmetic check rails improve appearance, especially on 00,  but I am sure functional check rails improve running. I have added lots of odd check rails, lengthened the short check rails on Peco code 100 points, put check rails across the lifting section baseboard joint and check railed a sharp curve in the garden where coaches kept running off the inside of the curve al with good results.

On 18/02/2019 at 17:16, RailWest said:

Nice checks rails indeed - but if you're going for authenticity, where is the trap-point at the exit from the loop/yard please ? :-)

 

 

There were lots of prototype locations where trap points probably should have been provided but were not.

Unless the line dropped appreciably away from the terminus i can't see the point of a trap.

That facing lead to the engine shed is where the trap is needed.

 

[RailWest]

>>>Unless the line dropped appreciably away from the terminus i can't see the point of a trap.....

 

I must disagree - the gradient is irrelevant in such circumstances. BoT Regulations were quite clear about the need to protect passenger lines from unauthorised moves off of goods line and I doubt that HM Inspector would have passed it without a trap. The prototype of course had a trap leading to a short spur.

 

I would agree that the road off to the left - if indeed to an engine-shed - would have needed a trap as well, but maybe it is just out-of-sight along with whatever signal controls its exit ?

[The Stationmaster]

Don't forget that in some situations a scotch block, working in correspondence with the points in the passenger running line, was acceptable in lieu of a trap point.  But to add to what Chris has already stated I would be amazed if the Inspectorate would have agreed the drawings of a proposed layout, let alone permitted on subsequent inspection,  failure to provide trap points (or explain why a scotch block was being substituted for trap points).  

 

I'd love to see examples of any location where trap points (or a worked scotch block) were not provided where they should have been provided.

[Edwin_m]

Even on a moderate adverse gradient (but sidings would normally be level), a strong wind could blow vans out of a siding if they had been left unbraked. 

[iands]

31 minutes ago, The Stationmaster said:

Don't forget that in some situations a scotch block, working in correspondence with the points in the passenger running line, was acceptable in lieu of a trap point.  But to add to what Chris has already stated I would be amazed if the Inspectorate would have agreed the drawings of a proposed layout, let alone permitted on subsequent inspection,  failure to provide trap points (or explain why a scotch block was being substituted for trap points).  

 

I'd love to see examples of any location where trap points (or a worked scotch block) were not provided where they should have been provided.

Apologies venturing/perpetuating off-topic from the original post, question if I may Mike. Instead of trap points (single-rail or double-rail), were there any occasions/examples when "de-railers" were utilised to protect a running line from a siding? (Yes, I know a trap point effectively de-rails a runaway/unauthorised move, but I'm thinking more of the device that is moved on to, or off of, the rail top). 

[uax6]

Yes, The K&WVR has a derailer at its boundary.

There are plenty of instances of worked scotches being used instead of traps. One that comes to mind is Magdelan Road, and my mates 7.25" railway!

 

Andy G

[bécasse]

29 minutes ago, iands said:

Apologies venturing/perpetuating off-topic from the original post, question if I may Mike. Instead of trap points (single-rail or double-rail), were there any occasions/examples when "de-railers" were utilised to protect a running line from a siding? (Yes, I know a trap point effectively de-rails a runaway/unauthorised move, but I'm thinking more of the device that is moved on to, or off of, the rail top). 

The LNER was particularly fond of the use of derailers worked from the box in lieu of trap points, although normally only where there were space limitations.

[31A]

22 hours ago, iands said:

Apologies venturing/perpetuating off-topic from the original post, question if I may Mike. Instead of trap points (single-rail or double-rail), were there any occasions/examples when "de-railers" were utilised to protect a running line from a siding? (Yes, I know a trap point effectively de-rails a runaway/unauthorised move, but I'm thinking more of the device that is moved on to, or off of, the rail top). 

 

21 hours ago, bécasse said:

The LNER was particularly fond of the use of derailers worked from the box in lieu of trap points, although normally only where there were space limitations.

 

For what it's worth, there's a derailer at the south end of Darlington Bank Top station, I think on the 'bypass' road on the up side beneath the train shed.  I don't know how long it's been there, but I remember that it did its job a few years ago!

[Penlan]

I had a check rail on Holywell town some 30+ years ago, somehow through social upheavals I still have the length of track.
It's original radius was about 80", but for the revised (becoming a roundy-roundy) Penlan, it's been sharpened to 52" radius.  Still to be laid - EM Gauge.
Gap is 1mm, same as check rails on points.  I don't recall any running problems (at 80").

 

Edited May 21, 2019 by Penlan

[Penlan]

On a 3 way point I have with 2 X 1:9 V's and 72" radius curves one of the check rails is about 8" long.
I've never had a problem with my EM gauge 0-6-0 loco's on them.

[Izzy]

On 19/02/2019 at 18:58, keefer said:

Burntisland in Fife on the ECML used to be checkrailed on both lines, with a PSR of, i think, 40mph.

https://www.geograph.org.uk/photo/1950667

 

More recent pics seem to show a checkrail on the Up (southbound) line only

https://www.geograph.org.uk/photo/3606902 (ignore the rails in the 4ft)

I'd have thought the tighter radius Down line would be more likely to need a checkrail?

 

On 19/02/2019 at 20:10, jim.snowdon said:

Since inside keying on bullhead track went out of fashion a great many decades before the second picture was taken, both roads in the second picture are check railed. Check rails are the only occasion where there are keys visible in the four-foot.

 

Jim

 

Puzzled by the second photo, no doubt my limited knowledge, but isn’t the track flatbottom with a bullhead checkrail? Is this normal/common and how is it possible ?

 

Izzy

[jim.snowdon]

1 hour ago, Izzy said:

 

 

Puzzled by the second photo, no doubt my limited knowledge, but isn’t the track flatbottom with a bullhead checkrail? Is this normal/common and how is it possible ?

 

Izzy

It's actually quite common, and requires a special combination baseplate/chair. I haven't got a picture myself, although I see some every time I go through Paddington station, and there are only mentions of them in my permanent way books. However, poking about the web, I discovered that the very same subject had been covered on RMW about 7 years ago -

Jim

 

 

[5050]

I've fitted check rails to the inside curve of the two 3-way points on my new work-in-progress (see 'New Beginnings' in standard gauge industrial section).  It's P4 but with very tight radii, approx 450mm/18" and will only be used with short wheelbase 4-wheel locos and stock.  I felt the need to ensure wheels are restrained from flange climbing as per the prototype and they have been set using the 'normal' flangeway gauge.  I have only managed a quick test with a loco at one end but it seemed to work OK.  I'm going to rig up a test with bits of wire to make sure both 3-ways work OK under power before I start the full wiring scheme!

 

 

This photo shows the check rail inside the inner curve of the point.  It continues round almost to the end of the blade.

[jim.snowdon]

Does the curve incorporate any gauge widening (as the prototype would)?

 

Jim

[sir douglas]

Greyhound Bridge in Lancaster on the Midland's Morecambe line, the bridge is curved quite tightly so had check rail on both lines all the the way across. it looks to be about 500-600ft radius. this was faithfully reproduced by Jamie by hand laying with c&l chairs

 

Edited May 25, 2019 by sir douglas

[5050]

2 hours ago, jim.snowdon said:

Does the curve incorporate any gauge widening (as the prototype would)?

 

Jim

I use the original triangular gauges which supposedly allow for this but with short wheelbase stock I don't think it is so important as on a layout with larger locos etc.

[jim.snowdon]

10 minutes ago, 5050 said:

I use the original triangular gauges which supposedly allow for this but with short wheelbase stock I don't think it is so important as on a layout with larger locos etc.

Thank you - the point I was going to make was that the check rail should be set by reference to the opposite running rail, so that the check flangeway is enlarged by the amount of the gauge widening.

 

There isn't a lot written about gauge widening for tight curves, but Summerson's 1895 guide for platelayers, which is quite useful for non-main line track, gives 120' as the practical minimum radius on standard gauge for stock having a wheelbase of about twice the gauge. It also includes a practical formula for calculating the amount of widening for longer vehicles, namely -

 

- for longest wheelbase = Gauge x 2, widening = 44/radius (in feet)

- for longest wheelbase = Gauge x 3, widening = 98/radius (in feet)

- for longest wheelbase = Gauge x 4, widening = 180/radius (in feet)

 

For some of the curves that could be found in dockyards and industrial areas, the effect this had in widening the check flangeway could be quite marked.

 

Jim