'Dew on train tracks blamed for delays'

[pendolino]

So says the Guardian: http://www.guardian.co.uk/uk/2011/feb/09/dew-delays-rail-service

I can understand that moisture causes poor rail-head conditions, but also that passengers find such a situation ludicrous and an unbelievable excuse for late running. But what can the railway do? Year-round sandite trains?

 

[OuterDistant]

That's the press for you!

Barely a decade after they were all running around screaming about trains going through red signals, now they're all running around screaming about measures taken to prevent it.

 

[The Barlow Boy]

I didn't read anything about them complaining about measures to prevent it but...Dew? This is the 21st century.

 

[Legzr1]

I didn't read anything about them complaining about measures to prevent it but...Dew? This is the 21st century.

Why not offer to go and dry all the tracks with a little tissue then?:roll:

Damp track = damp wheels = wheelslip = cut in power = loss of time.

Any part of that sentence you're struggling with?

Yes?

PM me.

 

[pendolino]

I didn't read anything about them complaining about measures to prevent it but...Dew? This is the 21st century.

It is, yes. But the technology that forms the basis for the railway is 19th century - metal on metal, and any substance that acts as a lubricant between the two will cause wheelslip, either on braking, or taking power, or both.

 

[The Barlow Boy]

The point I'm trying to make is that in the 21st century one would have thought that a transport system would cope with wet rails.
--- old post above --- --- new post below ---

Why not offer to go and dry all the tracks with a little tissue then?:roll:

Damp track = damp wheels = wheelslip = cut in power = loss of time.

Any part of that sentence you're struggling with?

Yes?

PM me.

You can take your sarcasm and shove it where the sun don't shine pal.
Damp road, damp wheels don't stop my car, damp runway damp wheels don't stop airlines. Damp rails, damp wheels trains stuffed. Any part of that statement you can't cope with?

 

[ralphchadkirk]

The point I'm trying to make is that in the 21st century one would have thought that a transport system would cope with wet rails.
--- old post above --- --- new post below ---


You can take your sarcasm and shove it where the sun don't shine pal.
Damp road, damp wheels don't stop my car, damp runway damp wheels don't stop airlines. Damp rails, damp wheels trains stuffed. Any part of that statement you can't cope with?

Tarmac to Rubber in both cases. Railways, metal to metal. It's really not that hard to understand! Metal to metal is always going to be affected with even the tiniest bit of contamination.

 

[Dai.]

May I also just point out on the car and plane business, if there is a change in the road/runway conditions with water, it's recommended that cars are to slow down, due to the friction issues and that planes are more careful landing and taking off.

 

[IanPooleTrains]

But what I don't understand is that rain/dew/ice/snow or any type of inclement weather has been a part of the planet for millennia now.

Sure, we have only had trains for a while but they never kicked up this much fuss when we had all of the snow and they were delaying trains and cancelling trains then

Surely the press know that weather is part of everyday life?

 

[Legzr1]

The point I'm trying to make is that in the 21st century one would have thought that a transport system would cope with wet rails.
--- old post above --- --- new post below ---


You can take your sarcasm and shove it where the sun don't shine pal.
Damp road, damp wheels don't stop my car, damp runway damp wheels don't stop airlines. Damp rails, damp wheels trains stuffed. Any part of that statement you can't cope with?

See the posts under yours.


Have you actually ever been on a train?
Looked at a picture?
Hell,even seen one on TV?




Amateurs :roll:

 

[Flamingo]

I didn't read anything about them complaining about measures to prevent it but...Dew? This is the 21st century.

Blame it on Global Warming then

 

[Via Bank]

You can take your sarcasm and shove it where the sun don't shine pal.
Damp road, damp wheels don't stop my car, damp runway damp wheels don't stop airlines. Damp rails, damp wheels trains stuffed. Any part of that statement you can't cope with?

Of course a damp road doesn't stop your car. It does, however, affect your car's acceleration and increases its braking distance, hence affecting traffic and increasing journey times.

Damp rails don't stop trains. They do, however, affect the train's acceleration and increase its braking distance, hence affecting traffic and increasing journey times.

Simples.

 

[Pacerpilot]

Incidentally, some of my worst low adhesion slides have been in the summer months after a sunshower.

 

[TDK]

Until you have driven a train under poor railhead conditions you would not understand the difficulty you have taking power, some units are better than others however a small amount of moisture be it dew or drizzle will cause poor railhead conditions any time of the year even in the 21st century, it cannot be predicted or evn forcast as it is usually a locl phenomina - as for the 21st century even with £25m computers the met office on many occasions get the forcast wrong, they cannot accurately predict earthquakes or volcanic eruptions and even poor railhead conditions

 

[O L Leigh]

Damp road, damp wheels don't stop my car, damp runway damp wheels don't stop airlines. Damp rails, damp wheels trains stuffed. Any part of that statement you can't cope with?

Sorry chap, but I've got to come down on the side of the others.

Dew is often the very worst condition because the droplets are small and so don't necessarily have sufficient mass to overcome their own surface tension meaning that it doesn't run off the railhead like rain can. And it isn't a new problem either. Low adhesion has been an issue ever since locomotives have been used to provide the motive power for trains.

There are technical aids to help overcome wheelslip, but they invariably involve cutting the power to allow the wheels to regain grip on the rail. Yes you can drop sand if you're in a particularly tight spot, but you can't drop it continuously and there's certainly no point in doing so until you've gained at least a certain amount of forward motion.

O L Leigh

 

[Geezertronic]

I would think that if you want to make a car comparison, then rubber on ice would be more akin to metal wheel on slippy metal rail. Don't know about others but even my 4WD Estate was slipping on the ice during the bad weather...

 

[Peter Mugridge]

I remember a picture in rail a few years ago of a rail burn from an uncontrolled wheelspin that was so severe it was about 90% the way through the rail... Am I right in thinking that happened in dew conditions?

 

[ChrisCooper]

Also, heavy rain will tend to wash any contaminants (oil, grease, crushed leaves etc) off the track, wheras dew will not. Had a number of experiances of what a bit of damp will do to rails, mostly with trams (well one particular tram) but also remember the "Southern Belle" railtour slipping like mad up from Folkstone to Shakespear Cliff Tunnel on a damp morning (plenty of smoke coming from the powered wheels). Must find the video one of these days.

 

[deltic1989]

with regard to the press..... They are never happy with anything they are always looking for something to complain about and call it "news". I fail to see how dew on railways can be regarded as news surely this has been happening since railways were invented? Also the press make a huge fuss about rail accidents (even train vs car at an LC is a train crash, railway always gets the blame), then when measures are put in place to prevent accidents maybe increaseing journey times by a few mins, they moan again. Theres no pleasing some folk.

 

[Kneedown]

Another factor is that modern passenger trains tend to be a lot lighter than their counterparts from the 50's and 60's, and so there is less friction between wheel and railhead, therefore less adhesion in damp conditions. It's simple physics.
It's a problem thats always been with us. The sandbox isn't a recent invention. The only reason it's become such an issue is a combination of much lighter trains and the media's hunger for a nice controversy that sells papers.

 

[ANorthernGuard]

we may be in the 21st Century but the railway is approx 170+ years old which still works on the same basic system, Dew/Drizzle on rails cause low adhesion has done since the dawn of the railway and will do until we stop either using rails or someone comes up with an idea that works....simples

 

[158747]

The point I'm trying to make is that in the 21st century one would have thought that a transport system would cope with wet rails.
--- old post above --- --- new post below ---


You can take your sarcasm and shove it where the sun don't shine pal.
Damp road, damp wheels don't stop my car, damp runway damp wheels don't stop airlines. Damp rails, damp wheels trains stuffed. Any part of that statement you can't cope with?

Rubber tyres on tarmac with a relatively large contact area, steel wheels on
steel rails with a minute contact area. It only takes a small amount of
contamination between the two to reduce the acceleration / deceleration of the train.

 

[asylumxl]

Surely there should be padding for these occurences, even in a non leaf fall timetable?

 

[NSEFAN]

Is it possible to fit a layer onto the traction wheels that would improve friction?

 

[Kneedown]

Is it possible to fit a layer onto the traction wheels that would improve friction?

Maybe, but all wheels would have to have the layer as all wheels are used for braking, and stopping the train is the really tricky bit, more so than starting. Such a layer would have to be electrically conductive to ensure operation of track circuits (TCA's only assist in the operation of track circuits, they can't be relied upon to actuate them on their own) In addition the layer would have to be resilient enough to withstand the hammering it'll get, as well as the wear of the brake blocks on tread braked trains, and smooth enough so as not to make the ride uncomfortable.

Is all this possible?

 

[asylumxl]

I'm sure it could be possible, but I believe it'd also increase track wear massively, so it won't happen.

 

[jopsuk]

Another factor is that modern passenger trains tend to be a lot lighter than their counterparts from the 50's and 60's

No they aren't... for example, a class 450 weights about the same as a 4CIG or 4REP- in fact, 377s (and therefore 375s) are about the same total weight too (all about 170 tonnes) for a four car set. Networkers are lighter- about 130 tonnes for a four car set.

The lightweight aluminium and plastic construction is needed to keep the weight down, as all the extra weight of a stronger construction and the aircon etc would make modern trains hilariously heavy.

 

[Kneedown]

No they aren't... for example, a class 450 weights about the same as a 4CIG or 4REP- in fact, 377s (and therefore 375s) are about the same total weight too (all about 170 tonnes) for a four car set. Networkers are lighter- about 130 tonnes for a four car set.

I can't comment on the Southern's toy trains, but up here we used to have real trains with a loco which were a heckuva lot heavier than the Sprinters which replaced em!

 

[ChrisCooper]

Another issue with modern trains is the switch from tread brakes to disk brakes. Tread brakes keep the wheel clean and tend to rough it up a little, so improving adheasion, wheras disk brakes to not. I don't really get the obsession with disks on everything these days, especially on EMUs with rheostatic/regenerative braking where the brakes are only being used at low speed (where tread brakes are more effective than disks). Even worse when on a lot of modern trains the disks are far noisier than any tread brakes. Disks are only needed for high speeds, although even the TGV and Eurostars use tread brakes on the powercars, which can be used from top speed.

 

[Clip]

Its worth pointing out that on last nights news NR refuted this and said it was down to a signal failure..