Swansea district line gauge error?

[truckman060473]

In Wikipedia it mentions something about the S.D.L being out of gauge due to incompetent rail maintenance and rendered the line suitable for slow freight movements. apparently there is an old american rule about rail gauge errors "out" by between 4' 8" and 4' 9 1/2" variations from the 4' 8 1/2" standard, limits that line to 60mph. so does a similar rule apply to the district line and when a faster passenger train (e.g. fishguard to cheltenham) makes use of this line is it restricted to 60mph?

 

[Old Timer]

In Wikipedia it mentions something about the S.D.L being out of gauge due to incompetent rail maintenance and rendered the line suitable for slow freight movements. apparently there is an old american rule about rail gauge errors "out" by between 4' 8" and 4' 9 1/2" variations from the 4' 8 1/2" standard, limits that line to 60mph. so does a similar rule apply to the district line and when a faster passenger train (e.g. fishguard to cheltenham) makes use of this line is it restricted to 60mph?

Track gauge variations of small amounts will not lead to a derailment. A derailment will occur when the wheel can run at the running edge of the rail and thus can force the rail outwards and the wheel "fall" in to the four foot. Speed here is irrelevant.

What may be more relevant is the relationship between the train and the lineside structures which will be related to speed and vehicle size. The area within which any vehicle moves is kinown as the dynamic kinematic envelope. This is the area between the static kinematic envelope and the swept kinematic envelope. This area will vary with speed and vehicle size.

Historically passneger vehicle were slightly wider than freight wagons, hence the classification C1, which refers for Coaching stock up to 9 feet 0 & 3/4 inches wide (over the door handles).

It was this width which required coaching stock to be treated as out of gauge when travelling within a freight train.

Sidings and freight only lines thus did not necessarily need to be maintained to the same gauge, and is the reason why on BR some lines/sidings were restricted to coaching stock.

Note that just to complicate matters some vehicles which were constructed originally as passenger vehicles, or which looked like passenger vehicles were actually gauged to freight standards and could pass without restriction. Such stock could pass over any freight line / siding without restriction and was known as NPCCS, which stood for "Non Passenger Carrying Coaching Stock"

GUVs and Siphon Gs are good examples.

Here is a picture of a GUV

http://images.google.co.uk/imgres?imgurl=http://www.bluebellrailway.co.uk/bluebell/pic2/vans/guv_davidc_21jan09h.jpg&imgrefurl=http://www.bluebellrailway.co.uk/bluebell/pic2/vans/guv93722.html&usg=__4JWjYM0a9fulkgkQUsI_l4A4zps=&h=768&w=1024&sz=177&hl=en&start=7&sig2=9Hsogaj-WIMye2LYCxjz6A&um=1&tbnid=OVIunu1QAsn5VM:&tbnh=113&tbnw=150&prev=/images%3Fq%3DGUV%2Bcarriage%26hl%3Den%26safe%3Doff%26rlz%3D1T4GGLL_en-GBGB352GB352%26sa%3DN%26um%3D1&ei=idEkS9emK8vV-Qaku8HFBg

Although the eagle eyed will notice it is stencilled C1, this was used to denote that it may pass as coaching stock in a passenger train. You will however notice the slab sides, which is where the width was taken out

 

[truckman060473]

very nice answer. but is there a speed restriction on the district line then? whenever i have travelled on it, be it class 37, 50 hauled or more recently a 2 unit 150 sprinter type the speed of the train never seems to get very high. after re joining the GW main line at Cwrt Sart jn. Briton Ferry the train really gets going then.

 

[Old Timer]

very nice answer. but is there a speed restriction on the district line then? whenever i have travelled on it, be it class 37, 50 hauled or more recently a 2 unit 150 sprinter type the speed of the train never seems to get very high. after re joining the GW main line at Cwrt Sart jn. Briton Ferry the train really gets going then.

Sorry, old chap I am not able to answer that question, however there is a speed restriction placed on passenger trains passing over freight only lines but it has been so long I cannot recall off the top of my head what it is. I have a feeling it is 20 mph but I could be wrong.

 

[The Planner]

50mph flat restriction, be it freight or passenger, cut up by a 20 at Dynevor Jn, 20/40 on the down through Llangyfelach tunnel and a bit of 30 and 20 on the down near Grovesend Colliery loop.

 

[Celtic Crusader]

I'm very much worried that the District Line with its loss of gauge and lack of use will eventually be rationalised under Network Rail plans. Freight only is one thing, but there are major structures across the route that need renewing in 5 years, a cost they may not be able to justify. They haven’t even considered returning passenger services to it:

Route 14 South and Central Wales and Borders

Its such a long run that a HST should have relatively little trouble of reaching 80mph, again, if weren't for that maintenance blunder, though I drive alongside the line I obviously have no idea what state the viaducts are currently in.

I hope I’m wrong, but am still anxious there may be a Post-Beeching Axe cut on the entire line once Hendy Junction via the Heart of Wales Line is sorted out. With a line of that size, no preservation society in the UK can hope to secure the route either or may use of it, there’s simply too much infrastructure to take on board.

 

[The Planner]

The district wont close, its a far too important diversionary route.

 

[Old Timer]

Having now read the relevant Wickipedia article after reading the DB Schenker letter, it is quite clear that the author of the Wickipedia item is completely confused about the use of the word "gauge".

It is not track gauge that is the issue but structure gauge, and reading between the lines it looks as it the track has just been continually tamped and the track "raised" thus reducing the clearance.

This is not an unknown phenomenom, indeed Network Rail Maintenance on one recorded occasion not only managed to tamp the track under a bridge at one location within the W6A gauge, but when they were told so, they went back and tamped it again, thus closing the line down to freight traffic until an emergency track lowering was carried out, fortunately by an Infrastructure Contractor otherwise God knows what would have happened :roll::roll: