View Full Version : Rail Networks - Hot Day chaos.

19th Jan 2009, 06:27
Another 40 deg C day here in Victoria (Oz)and the suburban railnetwork is falling down around our ankles..........again!!! Blaming hot weather for hundreds of cancelled trains, delayed trains sue to much lower speed restrictions.

So why does his happen. I thought the new continuously welded track eliminated the problems of expansion.

Any rail experts out there who can shed light on the subject?

19th Jan 2009, 06:44
Certainly not an expert but you're getting what we have just had in WA. That was a run of 14 days over 32C. There were no problems reported with the rail system here.

Perhaps it's because Victorians are not used to the heat :}

19th Jan 2009, 06:49
Metal expands with heat. Political and marketing spin may fool ignorant humans, but it cannot overcome the realities of physics.

19th Jan 2009, 07:23
Metal expands with heat.

Is that why it's taking longer for the train to get to the other end?

Windy Militant
19th Jan 2009, 08:55
Continuously welded rails can and do buckle because of the differential expansion due to the rails being heated at different rates due to being either exposed to sun light or shaded, especially if the hot spot is near the the middle of the span.
I was involved in a programme run by London underground about ten years ago where they scanned the tracks with a thermal imager to identify the hot spots. They then fitted thermocouples to the track at these points which fed this information to an automated system which controlled the speed of the trains. Prior to this they used to send a bloke with a thermometer to do this, apparently this has saved London transport a few millions and saved Londoners hours in delays since then.

19th Jan 2009, 10:43
You obviously are experiencing the "wrong kind of degrees".

In case you're unfamiliar with British terminology, in the third-world country that's England today, excuses for trains running late/not at all are usually "the wrong kind of leaves fell on the track", "the wrong kind of snow fell on the track", or "the wrong kind of rain fell on the track".

(But never: "the wrong administration is running the railways.")

19th Jan 2009, 11:04
Basil wrote:-
I don't know much about railroad (so clearly perfectly qualified to post on Prune http://static.pprune.org/images/smilies/badteeth.gif )
I'd guess there's a temperature range limit for continuously welded rail and have heard that there are gaps, albeit at much greater distances apart, and with the cut angled for smoother running.

That's the "breather".
With continuous welded rail the long rail lengths are hydraulically stretched then welded together. Expansion is suppressed by the fastenings along the rails and internal stresses occur. Eventually the rails need destressed by loosing the fastenings.
There is a temperature range the rails cannot cope with and the only way around it is for the engineers to "set up the rails" periodically. Biggest problems can occur if a sudden hot spell occurs when track was set up in cold wx.

I travel everywhere by car and avoid railway hassle.

19th Jan 2009, 11:45
[QUOTE][/in the third-world country that's England todayQUOTE]

The third world country that is the fifth largest economy on earth? Don't you just love ex-pats? Thank f*** you lot are overseas. Don't ever come back you whinging and self-justifying fools. Read this ex-pat:

UK Economy, United Kingdom Economy, UK GDP, Economy Of United Kingdom (http://www.economywatch.com/world_economy/united-kingdom/)

19th Jan 2009, 12:17
Didn't you check your post after you posted it?

Your quote is all cocked up. I never get it why people get their quotes all cocked up but don't do anything about it. :rolleyes:

Use the edit button.

19th Jan 2009, 12:59
Believe it or not we have the same problem in this country too in the summer. We call them "sun kinks".
We also have lots of problems in the winter: CANOE -- CNEWS - Canada: Frigid weather causes commuter headaches (http://cnews.canoe.ca/CNEWS/Canada/2009/01/14/8018606-cp.html)

Buster Hyman
19th Jan 2009, 13:20
Well...sadly, you get that with the belligerent & militant drivers we've got, but you'll not be hearing Krapsky saying this. Most of the rail problems stem from this 70's attitude of the rail union.

Contrary to sisemans TIC remark, we get this heat every year...yet somehow, this year, it's a big problem. I'm sure we've had the issue before, but I bet that next year, there won't be as many cancellations even though they will invest diddly squat on the tracks.

Anyway, you won't have to worry about Connex running the system soon.....;)

19th Jan 2009, 13:39
So why do we not go back to having expansion gaps every 60 feet?

19th Jan 2009, 16:39
The third world country that is the fifth largest economy on earth? Don't you just love ex-pats? Thank f*** you lot are overseas. Don't ever come back you whinging and self-justifying fools. Read this ex-pat:

I did, and the figures in the report are from 2003-2006.

Last time I looked at my calender it's at least three years later...

19th Jan 2009, 16:46
>So why do we not go back to having expansion gaps every 60 feet? <

It's not as 'efficient'. That means it needs a LOT more maintainance, especially if there's a high unsprung weight battering the rail ends. More maintainance costs more, and as far as the third world country known as the UK is concerned, that means lower bonuses for upper management. But in the days of fishplated track, such problems were less common. Whether such track would stand up to regular running at over 100mph without an awful lot of maintainance is another matter

Back in 1961, when Gerald Fiennes was the Regional Manager for British Railways Eastern Region, a train arrived in Kings Cross from Doncaster very late. Fiennes told the announcer how to phrase the apology and she refused. He did the announcement on the lines of 'This is the Regional Manager. British Railways apologise for the late arrival of the train from Doncaster. This was caused by management incompetence'. Not that he didn't screw things up with bad management decisions when he moved to the Western Region.....

Of course, the best example of how NOT to privatise a nationalised railway system is what happened in the UK....

19th Jan 2009, 16:57
Expansion gaps every 60 feet requires much more maintenance, are less comfortable for passengers and they carry a higher risk of broken rails.
Whe the gap has to be fairly wide every wheel hits the rail end like a hammer blow and since the rail ends are drilled to take the fishplates there is an inherent weekness right where the thump is felt.

Public transport - :mad:

20th Jan 2009, 00:13
Bwahahaha! It's come down to slagging off expats, who reply, and cannot spell 'calendar' (which, I hope, will be next).

To get things back on the rails (snigger) they had to shut down and rework large sections of exposed track on the Piccadilly and Derelict lines in 2006 during a ghastly summer (at other times, they worked at reduced, i.e., walking pace). It wasn't as hot as it is in Viccie, but you didn't have snow on them earlier in the year, either.

The only ones I know of that don't screw up too often due to weather are the Japanese ,French and German lines, all of which are subject to extremes.