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Offline H0  
#1 Posted : 25 June 2020 13:05:24(UTC)
H0


Joined: 16/02/2004(UTC)
Posts: 13,749
Location: DE-NW
Are you still painting your rails in rusty brown?

Deutsche Bahn are painting some rails white to reduce the heat-up in Summer. Currently this is a local test. And now the hot days have come and they can see if the paint makes a difference.

German news article:
https://www.t-online.de/...n-das-ist-der-grund.html
Regards
Tom
---
"In all of the gauges, we particularly emphasize a high level of quality, the best possible fidelity to the prototype, and absolute precision. You will see that in all of our products." (from Märklin New Items Brochure 2015, page 1) ROFLBTCUTS
UserPostedImage
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Offline PJMärklin  
#2 Posted : 25 June 2020 14:18:45(UTC)
PJMärklin

Australia   
Joined: 04/12/2013(UTC)
Posts: 1,547
Location: Hobart, Australia
Hello Tom,Smile

Over the last 5 years or so I have noticed that some of the rails on the railway causeway to Venice seemed
to be painted white OhMyGod and I have posted some images of same on this great Users Group:


UserPostedImage


UserPostedImage


UserPostedImage


This resulted in some discussion on this forum after my post which wondered if this was to counter the effects of heatWink :



Regards,


PhilipBigGrin
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Offline mbarreto  
#3 Posted : 26 June 2020 11:40:22(UTC)
mbarreto

Portugal   
Joined: 18/02/2008(UTC)
Posts: 941
It is more interesting to find a way to transform that heat energy in some useful energy rather than reflect it out. I don't know if there is some practical way of doing it and probably if it was easy and profitable it was already in test or production.


Mostly Märklin H0.


Offline DaleSchultz  
#4 Posted : 26 June 2020 14:22:23(UTC)
DaleSchultz

United States   
Joined: 10/02/2006(UTC)
Posts: 3,395
its hard to believe that this works.

A black object radiates and absorbs heat faster, so painting the sides of the rail white is going to slow the rate at which heat radiates from it. The sides are not perpendicular to the sun's rays, so I would expect a net increase in temperature by painting the sides white.
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline mbarreto  
#5 Posted : 26 June 2020 15:04:45(UTC)
mbarreto

Portugal   
Joined: 18/02/2008(UTC)
Posts: 941
Originally Posted by: DaleSchultz Go to Quoted Post
its hard to believe that this works.

A black object radiates and absorbs heat faster, so painting the sides of the rail white is going to slow the rate at which heat radiates from it. The sides are not perpendicular to the sun's rays, so I would expect a net increase in temperature by painting the sides white.


They need to use kind of a Goretex paint. Just it needs to work for sun radiation instead work for breath ;)


Mostly Märklin H0.


Online kiwiAlan  
#6 Posted : 26 June 2020 20:05:16(UTC)
kiwiAlan

United Kingdom   
Joined: 23/07/2014(UTC)
Posts: 5,144
Location: ENGLAND, Didcot
Originally Posted by: DaleSchultz Go to Quoted Post
its hard to believe that this works.

A black object radiates and absorbs heat faster, so painting the sides of the rail white is going to slow the rate at which heat radiates from it. The sides are not perpendicular to the sun's rays, so I would expect a net increase in temperature by painting the sides white.


But surely half the problem is the rails absorbing heat, so the white will slow down the absorption, which will mean they don't reach the same temperature during the day, and hence the rail expansion will be lower.
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Offline bph  
#7 Posted : 27 June 2020 00:05:23(UTC)
bph

Norway   
Joined: 04/08/2018(UTC)
Posts: 186
it will certainly help a bit. And it will be a boring, but safe job..........
000_1kl8v3.668c4122509.original.jpg
as a side note, most ship superstructure are white, to reflect as much light/heat as possible
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Offline Purellum  
#8 Posted : 27 June 2020 04:51:35(UTC)
Purellum

Denmark   
Joined: 08/11/2005(UTC)
Posts: 3,216
Location: Mullerup, 4200 Slagelse
Cool

It works well on wind turbines BigGrin

25 - 30 years ago, the first wind turbines were grey, because they were galvanized.

In Scandinavia, this was not a problem; but when the first turbines were installed in Texas, the grey towers got so hot that it
was hard to work inside; even though the heat-producing parts like the generator etc. is above the tower, in the nacelle.

Painting them white reduced the average temperature in the towers with more than 10 degrees Celsius.

This is what I was told; apparently there are a few reasons more: https://interestingengin...posite%20rotor%20blades.

Per.

Cool
If you can dream it, you can do it!

I, the copyright holder of this work, hereby release it into the public domain. This applies worldwide.

In case this is not legally possible:
I grant anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.

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Offline PJMärklin  
#9 Posted : 27 June 2020 06:49:53(UTC)
PJMärklin

Australia   
Joined: 04/12/2013(UTC)
Posts: 1,547
Location: Hobart, Australia
Originally Posted by: Purellum Go to Quoted Post
Cool

It works well on wind turbines BigGrin

25 - 30 years ago, the first wind turbines were grey, because they were galvanized.

In Scandinavia, this was not a problem; but when the first turbines were installed in Texas, the grey towers got so hot that it
was hard to work inside; even though the heat-producing parts like the generator etc. is above the tower, in the nacelle.

Painting them white reduced the average temperature in the towers with more than 10 degrees Celsius.

This is what I was told; apparently there are a few reasons more: https://interestingengin...posite%20rotor%20blades.

Per.

Cool



Thanks Per for : https://interestingengin...posite%20rotor%20blades. - I really liked the underview of the Spitfire ThumpUp
Offline river6109  
#10 Posted : 27 June 2020 10:24:20(UTC)
river6109

Australia   
Joined: 22/01/2009(UTC)
Posts: 13,071
Location: On 1965 Märklin Boulevard just around from Roco Square
Loco drivers complained about the white rails, you can't see them in winter time when the tracks are covered with snow and therefore you don't know where you going
https://www.youtube.com/river6109
https://www.youtube.com/6109river
5 years in Destruction mode
50 years in Repairing mode
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Online kiwiAlan  
#11 Posted : 27 June 2020 11:51:40(UTC)
kiwiAlan

United Kingdom   
Joined: 23/07/2014(UTC)
Posts: 5,144
Location: ENGLAND, Didcot
Originally Posted by: river6109 Go to Quoted Post
Loco drivers complained about the white rails, you can't see them in winter time when the tracks are covered with snow and therefore you don't know where you going


LOL LOL LOL LOL LOL LOL LOL LOL LOL LOL LOL LOL LOL LOL LOL LOL LOL
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Offline dominator  
#12 Posted : 27 June 2020 13:11:31(UTC)
dominator

New Zealand   
Joined: 20/01/2015(UTC)
Posts: 850
Location: Kerikeri
Sorry to side track. During WW2, an RAF person was sitting at an airfield when a civilian plane took off. He watched it for a while, looked down, then found it hard to see it again. He made inquiries and found out it was painted a pale green. Thats why WW2 British aircraft most often were painted pale green underneath.
Interestingly, the lightened spitfires [ no armaments etc to help them go faster ] used for spying, were painted pink, so they could not be seen coming out of the sun. They used these apparently to track coastal installations deemed dangerous to the allies, and the flew very low over the sea and coast taking pictures.

Cant remember where I read about that.



With the modern technique of welding rails together, there was now no ability to absorb expansion [ talked about in the films mentioned by ShannonN ] that I could work out.
Dereck


Couldn't resist when spitfires were mentioned. But I did get back on track.Flapper Flapper
Northland. NZ REMEMBER 0228 for ä
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Online kiwiAlan  
#13 Posted : 27 June 2020 13:43:25(UTC)
kiwiAlan

United Kingdom   
Joined: 23/07/2014(UTC)
Posts: 5,144
Location: ENGLAND, Didcot
Originally Posted by: dominator Go to Quoted Post

Interestingly, the lightened spitfires [ no armaments etc to help them go faster ] used for spying, were painted pink, so they could not be seen coming out of the sun.


I understood they were painted sky blue like the picture above in this thread so they were less easily seen against the sky. But the bigger problem they had was they were flying so high they left vapour trails, so apparently part of the job was adjusting your height to minimise these trails as it gave those on the ground clues as to where the plane was and its heading.

There may have been others painted pink, but I haven't seen that mentioned anywhere or photos of them.
Offline DaleSchultz  
#14 Posted : 27 June 2020 14:27:37(UTC)
DaleSchultz

United States   
Joined: 10/02/2006(UTC)
Posts: 3,395
Originally Posted by: kiwiAlan Go to Quoted Post

But surely half the problem is the rails absorbing heat, so the white will slow down the absorption, which will mean they don't reach the same temperature during the day, and hence the rail expansion will be lower.


yes, but the sides of the rails are vertical, and the solar flux comes from above, so the effectiveness of blocking the sun's rays will be limited by the angle of incidence of the rays.

In other words the sides of the rail is not where a lot of the heat gets into the rail. Black sided rails would radiate as much as possible.

It makes sense to paint surfaces that face the sun, such as a roof.

Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline torle  
#15 Posted : 27 June 2020 22:59:28(UTC)
torle

United States   
Joined: 05/06/2004(UTC)
Posts: 8
Thee Austrians are way ahead:


-=tom=-
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Offline DaleSchultz  
#16 Posted : 28 June 2020 01:30:15(UTC)
DaleSchultz

United States   
Joined: 10/02/2006(UTC)
Posts: 3,395
Hello Tom!

long time no hear! Glad to see you are here!
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
Offline Carim  
#17 Posted : 28 June 2020 12:36:22(UTC)
Carim

United Kingdom   
Joined: 15/09/2014(UTC)
Posts: 433
Location: London
If you can access the "BBC iPlayer", see the program "Inside Central Station", Series 1: Episode 2 at about 54:44 into the episode, you can see Network Rail painting the rails in Scotland.

Carim
Online kiwiAlan  
#18 Posted : 28 June 2020 17:34:17(UTC)
kiwiAlan

United Kingdom   
Joined: 23/07/2014(UTC)
Posts: 5,144
Location: ENGLAND, Didcot
Originally Posted by: torle Go to Quoted Post
Thee Austrians are way ahead:

-=tom=-


Next years Insider wagon ???
Offline Copenhagen  
#19 Posted : 29 June 2020 01:47:19(UTC)
Copenhagen


Joined: 23/04/2019(UTC)
Posts: 50
Originally Posted by: DaleSchultz Go to Quoted Post
Originally Posted by: kiwiAlan Go to Quoted Post

But surely half the problem is the rails absorbing heat, so the white will slow down the absorption, which will mean they don't reach the same temperature during the day, and hence the rail expansion will be lower.


yes, but the sides of the rails are vertical, and the solar flux comes from above, so the effectiveness of blocking the sun's rays will be limited by the angle of incidence of the rays.

In other words the sides of the rail is not where a lot of the heat gets into the rail. Black sided rails would radiate as much as possible.

It makes sense to paint surfaces that face the sun, such as a roof.



The sun is never vertical above the tracks in Germany. Even if it was it would only be for a quite limited time each day. So white on the sides is still less heat.
Offline PeFu  
#20 Posted : 29 June 2020 09:16:08(UTC)
PeFu

Sweden   
Joined: 30/08/2002(UTC)
Posts: 758
Interesting (?) facts on suncurves from the Swedish Transport Administration:

Welded rails should be laid during neutral conditions, e.g. approx. in the areas average temperature. In these conditions, rails are laid without having any tension.

Proper laid welded rails should not move at all.

On welded tracks, suncurves generally only occur

- when there are bad fastenings to the concrete sleepers or bad ballast OR
- if they are laid under non-neutral conditions OR
- in areas close to turnouts or non-welded sections.

Suncurves still occur every year even on welded tracks, mainly due to lack of funding for maintenance.

There are bigger challenges in northern Europe than in southern Europe, due to the wider span in temperatures.

MY OWN CONCLUSION: Painting the rails is a temporary solution for managing badly laid or badly maintained tracks.

Cool
The Great Krok!
Inspired by Swiss railways SBB/BLS, C and K track, CS2, TrainController Gold V9
Offline jerdenberg  
#21 Posted : 29 June 2020 10:24:54(UTC)
jerdenberg

Netherlands   
Joined: 10/01/2005(UTC)
Posts: 965
Location: Den Helder, Noord-Holland
A difference between the sides and the top of rails that are regularly used is that the top is fairly reflective (being "polished" by the wheels of the passing trains), while the sides tend to go brown …
Figomima division, UP; mostly figment of my imagination yet.
Online kiwiAlan  
#22 Posted : 29 June 2020 13:33:55(UTC)
kiwiAlan

United Kingdom   
Joined: 23/07/2014(UTC)
Posts: 5,144
Location: ENGLAND, Didcot
Originally Posted by: Copenhagen Go to Quoted Post

The sun is never vertical above the tracks in Germany. Even if it was it would only be for a quite limited time each day. So white on the sides is still less heat.


In the UK you would set a solar panel at about 55 degrees and it will get roughly even illumination at the extremes of sun altitude (i.e. longest and shortest days).

I would think that Germany would be at a similar enough angle, so painting the sides of the rails would be worth while.
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