West Somerset Railway General Discussion

Many thanks - thought a second Manor was on the agenda!

I suspect the peak season will be a little tense for the West Somerset with a fleet of 5 to cover is it 3 diagrams?

Steven

 

We already have a number of war time 45' rail lengths which came from the USA in the WSR main line.

But they are welded up in fours to make 180' and so equivalent to 3 British standard 60' lengths.

Robin

 

Oh no! Miss Type has struck again. Insert your choice of expletive *******************

 

FB or BH? Were they welded on installation or subsequently?

 

On installation, shortly postwar. Bullhead.

Robin

 

Foxcote Manor Society social media accounts posted yesterday:

"Speaking of which, 7822 is hopefully going to be back in steam in a few weeks and we are all looking forward to seeing her back".

So that would mean the peak season would be over before it would be available. Although no official announcements have been made its now very unlikely to visit WSR this season.

 

As has been stated, You can weld up any rails, but some are better than others.
BH rail joints can be welded but they are slightly more awkward to set up than FB joints.
It is best if you can cut off the bolt holes to remove any chance of rail flaws in the bolt hole areas, then weld up a series of joints into no more than 120fts and insert a closure rail to make up the difference in rail lengths.
If welding up rails into 120fts consideration should be given to welding as a priority any non standard or junction plates due to the greater cost of new replacement plates.

 

As I understand it the gaps in between rails are there to compensate for the expansion of the steel in hot weather , or is this an ' old wives tail '? On the big railway and the WSR so I'm told on this forum some of the rails are welded . My question is if expansion is involved how is it dealt with ? Thank you .

 

OK, here comes the science bit.

The coefficient of expansion of steel is around 0.000012. So a 60' rail at 10 degrees C will expand by a little under one fifth of an inch at 30 degrees C (and contract by the same amount at minus 10 degrees C). Three such lengths welded together (or 4 x 45') will change by just over half an inch with the same temperature changes. This is about how much expansion conventional bolted rail joints can deal with.

Long lengths of continuously welded rail will try to expand and contract even more but modern track fittings will hold that back a bit. However, CWR is provided with long expansion joints to cope with a diagonal slice between the rails see photo below).

Hope that helps

Robin

 

Relating this to the WSR, Next time you go round watchet curves, keep an eye out for a joint like this. Its quite close to mineral line bridge.

 

CWR is also generally under allot more tension than bolted rails.

 

Thank you for that Robin , I've never seen an expansion joint before but I saw your picture before I read your text and knew exactly what it was . I haven't even thought about coefficient of expansion since 'O' level physics but do understand it . Once again thanks .

 

The calculation for Stressing CWR is
e = extension in mm
L length of free rail in metres.
X = coefficient of expansion of steel 0.0000115
t = difference between actual average rail temp and required Stress Free Temp 27C

So for example T = 11, L = 300
From this we can find e the extension required.

27 - 11 = 16
16 x 300m = 4800
0.0000115 x 1000 = 0.0115
4800 x 0.0115 = 55.2mm = e

 

We've been stressing CWR on the GWSR, and you can see a video of rail stressing here:

 

I should add that there are limits as to the length possible to pull due to curveature.
On a straight the max possible is 900m each way in one pull.
Add a curve in and the length drops quickly .
For example from a straight down to a radius of 4000m 900m each way is possible.
4000 - 2001m = 600m each way
600m - 401m = 150m ew
below 400 = 100m

A further limit is imposed by a maximum pull force of 58 tonnes on the stressing gear.

 

Having been on the WSR today 7822 was still expected - if a little late!

 

I feel like an expert now , lol . I do miss the clickity clack however .

 

Lots of nonsense is talked about track, often by those who should know better. The physics and the maths are relatively simple.

Robin

 

Lots of nonsense talked about many topics on here. Track is not, however, simple when considering life time costs, optimum alignment, noise transmission etc. etc. and could be why the long standing Permanent Way Institute exists.

 

Agreed.

As a mere operator (but a scientist by degree) I started to learn about the physics and mathematics of track when I went on the Derailment investigation course Run at Derby Techical Centre some years ago. My railway bookshelves have several editions of 'British Railway Track.'

You are right to mention the professional body. These are not expensive to join and can be a valuable source of access to experience for heritage railway employees and volunteers. I would heartily teccomrnd the Institute of Railway Operators to heritage railway operational staff, for example. The Institute of Railway Signal Engineers has a very active 'minor railways' section.

Robin