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Discussion in 'Infrastructure & Stations' started by BRX, 19 Apr 2010.
Usually around points and crossovers as far as I can see. What's that all about?
I have always been under the impression that it's a H&S thing to make the moving parts and check rails more visible to track staff?
It's meant to reflect heat and so reduce expansion in the switch rails which could knock out the points detection in the signalling system.
I gather from a friend it P-Way that it is used to reflect heat radiation to reduce the expansion of rails, which can interfere with equipment like points detection.
Nope, all track should be treated with the same respect, points or not, and dont use the H&S line.
It is what them above said, works quite well to.
If the bits that are painted white are rail ends, then the purpose is for H+S reasons.
Its the switch part of points and crossings, if yours is the case why are the ends of 3rd rails not being painted, I would say they are more dangerous!
I don't know of any place that has done that Ploughman. It's for the reasons stated above.
One place where it's been done is East Croydon:
But interestingly not the switch rails on the points.
Could it be that there are 2 reasons for painting bits of track depending on what bit is done?
You often see disused bits of track where the points have been removed, and the ends of the rails formerly connected to the points have been painted either white or yellow. So the logical explanation would be to show drivers/staff that the rails are missing.
Yes, definitely. Just painting the end of a rail white would have no effect on expansion; it's clearly been done to make the rail end more visible.
The paint on the end of the juice rails, check rails etc is also for the crews of the unimat (and similar machines) in the background in E croydon sidings (Unimats being s&c tampers primarily).
Just highlights them for the operators as they tamp through (if viewed from above, everything else that does not want a visit from a tamping tool. eg cables , pipes, clamps etc, also gets a dose of white paint)
Not me using the H&S line; just saying what I was told when I asked about it.
But from having seen the photo of East Croydon in a later post, perhaps I should add that I live on the 3rd rail territory, so maybe I was being given an answer based purely on the local practice?
I can, however, see at least three check rails with white ends in that picture as well as the numerous live rail ends.
............or perhaps the "cut" end of the rail is more susceptible to corrosion ?
If you intend reusing a flame cut end of rail and more than 24 hours has passed since cutting then 150mm must be cut from the rail end, due to oxidisation.
Same shift the ends can be trimmed approx 25mm by disc.
If it was disc cut initially then this is not required.
When cutting into CWR the initial cut must be flame cut and not disc.
Subsequent cuts after stress released can then be disc'd
Rail ends are painted white all over the country not just in 3rd rail areas.
H+S as stated earlier and also as stated earlier for tamping works.
I believe rails are often painted white around the area of points to observe flange back contact (where the flange of the wheel is damaging the rail) and if the damage caused is excessive then conditions of P-Way, switch openings etc will be observed to ensure they are within the maintenance specifications and corrected if not.
So how would a flange contact the outside of the running rail? If it did then flange contact wear would be the last of your problems .
At Guildford most of the points have been white-washed around the switch and closure rail areas, the way it has been slapped on is not very scientific
i shouldnt imagine the application of paint is particularly accurate nor does it need to be, and whilst white paint may perhaps be used for other purposes i am very sure that this is one of those purposes
By painting the rails the level of flange back contact can be measured.
also earlier posts claiming that white paint is used to deflect heat, surely this cant be the case as expansion joints are provided? and surely consideration is given when calculating for expansion/contraction when rail is welded and stressed?
Expansion joints are provided in the plain line near the points, the bits of the points that are painted are the switch and closure rails, part of the reason is as these bits expand then detection is lost so the signals cannot be cleared.
Point noted!, although i can assure you that during maintenance of points inspection of the switch and closure rails is carried out to observe signs of flange back contact and white paint is sometimes, not always used to observe the level of flange back contact.
points are set up to tolerances which would allow for slight expansions in the rail i.e detection will be made at 1.5 mm but should fail at 3.5mm (gap between switch and closure rail)
There are at least five reasons to paint rails...
1) The rail ends are painted as a safety measure as shown in the photo.
2) Rails through level crossings are painted with a protective paint to help reduce the corrosion caused by road salt. Was usually a thick cream coloured paint, but current practice is to use rails sprayed with an aluminium coating.
3) Switches are painted white to help keep them cool, and so reduce thermal expansion and the resulting detection problem. This effect is worst on switch diamonds.
4) Paint is used to monitor the contact between wheels and check rails at crossings.
5) S&C emergency spares not for immediate use are often painted to prevent corrosion.