Hi all.

Here's one of those things that has puzzled me recently. At the point
on my regular commute where the train invariably stops at a signal,
some new rail has been left in the 4-foot, presumably waiting to be
installed. Now, it's been there several weeks and has grown a nice
layer of rust. The entire rail has a nice all over rust brown colour.

OK, fair enough, but the running rails next to it are not rusty at all.
The top surface of the rail is bright and shiny as expected, but even
those parts that are not in contact with train wheels are not rusty,
just a dull metallic grey colour. The contrast between the two rails is
very marked since they are only inches apart What mechanism prevents the
non-contacting parts of running rails from rusting?

Cheers

mark-r

-- 
"Let's meet the panel. You couldn't ask for four finer comedians -
so that answers your next question..."
 -- Humphrey Lyttleton

I've been wondering the same since we had some new rail left round here 
too! Some of it seems to be turning blue!!



Mark Robinson wrote:

> Hi all.
> 
> Here's one of those things that has puzzled me recently. At the point
> on my regular commute where the train invariably stops at a signal,
> some new rail has been left in the 4-foot, presumably waiting to be
> installed. Now, it's been there several weeks and has grown a nice
> layer of rust. The entire rail has a nice all over rust brown colour.
> 
> OK, fair enough, but the running rails next to it are not rusty at all.
> The top surface of the rail is bright and shiny as expected, but even
> those parts that are not in contact with train wheels are not rusty,
> just a dull metallic grey colour. The contrast between the two rails is
> very marked since they are only inches apart What mechanism prevents the
> non-contacting parts of running rails from rusting?
> 
> Cheers
> 
> mark-r
> 

maybe there is an electrolytic current set up in the rails, with the
wearing surfaces oxidizing more rapidly and a flow of electrons such
that the non wearing surfaces dont rust... the oxidized layer on the
running rail being taken off by the passing trains. Alternatively the
electron flow in the track circuitry might do the same job. Sort of
like galvanizing with zinc plating.
But it's been a long time since I studied that.

David

"Mark Robinson"  wrote in message 
news:432977F1.BD847877@simsol.co.uk...

>
> Hi all.
>
> Here's one of those things that has puzzled me recently. At the point
> on my regular commute where the train invariably stops at a signal,
> some new rail has been left in the 4-foot, presumably waiting to be
> installed. Now, it's been there several weeks and has grown a nice
> layer of rust. The entire rail has a nice all over rust brown colour.
>
> OK, fair enough, but the running rails next to it are not rusty at all.
> The top surface of the rail is bright and shiny as expected, but even
> those parts that are not in contact with train wheels are not rusty,
> just a dull metallic grey colour. The contrast between the two rails is
> very marked since they are only inches apart What mechanism prevents the
> non-contacting parts of running rails from rusting?
>
> Cheers
>
> mark-r


Do trains earth their electrical systems via the rails?

On Thu, 15 Sep 2005 14:32:33 +0100, Mark Robinson 
wrote:


>
>Hi all.
>
>Here's one of those things that has puzzled me recently. At the point
>on my regular commute where the train invariably stops at a signal,
>some new rail has been left in the 4-foot, presumably waiting to be
>installed. Now, it's been there several weeks and has grown a nice
>layer of rust. The entire rail has a nice all over rust brown colour.
>
>OK, fair enough, but the running rails next to it are not rusty at all.
>The top surface of the rail is bright and shiny as expected, but even
>those parts that are not in contact with train wheels are not rusty,
>just a dull metallic grey colour. The contrast between the two rails is
>very marked since they are only inches apart What mechanism prevents the
>non-contacting parts of running rails from rusting?
>

To some extent the accumulation of rust on running rails is probably
inhibited by vibration and the flexing of the rails when trains pass
over. There will also be variable amounts of "rust-proofing" due to
oily contamininants spread by some trains.
-- 
                                                             _______
 +---------------------------------------------------+      |\\   //|
 | Charles Ellson: charles@e11son.demon.co.uk        |      | \\ // |
 +---------------------------------------------------+      |  > <  |
                                                            | // \\ |
                                              Alba gu brath |//___\\|

- And on Thu, 15 Sep 2005 14:32:33 +0100, it was spake thus  said in message Mark Robinson :


> Here's one of those things that has puzzled me recently. At the point
> on my regular commute where the train invariably stops at a signal,
> some new rail has been left in the 4-foot, presumably waiting to be
> installed. Now, it's been there several weeks and has grown a nice
> layer of rust. The entire rail has a nice all over rust brown colour.
> 
> OK, fair enough, but the running rails next to it are not rusty at all.
> The top surface of the rail is bright and shiny as expected, but even
> those parts that are not in contact with train wheels are not rusty,
> just a dull metallic grey colour. The contrast between the two rails is
> very marked since they are only inches apart What mechanism prevents the
> non-contacting parts of running rails from rusting?
> 
> mark-r


Have you thought that the rails that are now in the 4' could be the old
running rails that were changed very quickly overnight/weekend/whilst you
were away for the ones you now see as the running rails...?
-- 
Nick

All my own comments !

Worked on the Signalling in the North East since 1983 !

http://www.whelan.me.uk
nrw7 on Yahoo messenger & nickw7coc on MSN Messenger too !

On Thu, 15 Sep 2005 18:19:59 +0000 (UTC), "Niall Wallace"
 wrote:


>
>"Mark Robinson"  wrote in message 
>news:432977F1.BD847877@simsol.co.uk...
>>
>> Hi all.
>>
>> Here's one of those things that has puzzled me recently. At the point
>> on my regular commute where the train invariably stops at a signal,
>> some new rail has been left in the 4-foot, presumably waiting to be
>> installed. Now, it's been there several weeks and has grown a nice
>> layer of rust. The entire rail has a nice all over rust brown colour.
>>
>> OK, fair enough, but the running rails next to it are not rusty at all.
>> The top surface of the rail is bright and shiny as expected, but even
>> those parts that are not in contact with train wheels are not rusty,
>> just a dull metallic grey colour. The contrast between the two rails is
>> very marked since they are only inches apart What mechanism prevents the
>> non-contacting parts of running rails from rusting?
>>
>> Cheers
>>
>> mark-r
>
>Do trains earth their electrical systems via the rails? 
>

Electric trains on NR pass the juice through the rails (well, one of
them anyway), if you'll excuse me stating the bleedin' obvious [TM]. A
small voltage difference to local earth will not be unusual.
-- 
                                                             _______
 +---------------------------------------------------+      |\\   //|
 | Charles Ellson: charles@e11son.demon.co.uk        |      | \\ // |
 +---------------------------------------------------+      |  > <  |
                                                            | // \\ |
                                              Alba gu brath |//___\\|

Nick wrote:

> Have you thought that the rails that are now in the 4' could be the old
> running rails that were changed very quickly overnight/weekend/whilst you
> were away for the ones you now see as the running rails...?


They new rails they fitted on our line were stored in the 4 foot for 
months and looked like described in this thread.

The old ones which are stacked at a location further down the line, 
after 2 months don't look rusty like the new ones did yet!

- And on Fri, 16 Sep 2005 10:08:34 +0100, it was spake thus  said in message Mark Robinson :


> 
> Thanks to eveyone for the replies!
> 
> Nick wrote:
> > Have you thought that the rails that are now in the 4' could be the old
> > running rails that were changed very quickly overnight/weekend/whilst you
> > were away for the ones you now see as the running rails...?
> 
> They look unworn, and have scribbled notes on them which would suggest
> that they're new. Having said that, there have been some weekend
> possessions and the ballast has been tinkered with, so maybe.
> 
> I think the most likely explanation is the years of accumulated slime
> prevent rust formation. Looking at a rarely used section of line
> confirms this I think, because the top of the rail (where the slime is
> worn off by the occasional train) rusts, but the non-contacting surfaces
> look much like the main line.
> 
> Cheers
> 
> mark-r



Any chance of some photos Mark, that'd resolve this once and for all ;)
-- 
Nick

All my own comments !

Worked on the Signalling in the North East since 1983 !

http://www.whelan.me.uk
nrw7 on Yahoo messenger & nickw7coc on MSN Messenger too !

Nick wrote:

> 
> Any chance of some photos Mark, that'd resolve this once and for all ;)


I've not been dragged into the 21st century yet so I don't have a
digital camera or camera phone! 

One of Darren's photos here:

http://photos.sudbury-branchline.co.uk/displayimage.php?album=3&pos=3

shows the effect quite well. Here the rails in the 4-foot are
noticably rustier than the running lines.

Cheers

mark-r

-- 
"Let's meet the panel. You couldn't ask for four finer comedians -
so that answers your next question..."
 -- Humphrey Lyttleton

Nick wrote:

> Any chance of some photos Mark, that'd resolve this once and for all ;)


I've got a few from the works on the Sudbury line where the new rail was 
similar to that described.

http://makeashorterlink.com/?Q10C62FCB That rusty rail between the two 
lines *was* the new track that got fitted

http://makeashorterlink.com/?A11C44FCB is another photo with it shown 
again between the 2 lines

http://makeashorterlink.com/?E34C12FCB is it being fitted.

http://makeashorterlink.com/?L15C25FCB There it is after being tampered once

And finally
http://makeashorterlink.com/?Q17C32FCB There it is about 3 days after 
line reopened