What are "poor rail head conditions"?

[trainophile]

The above has been given as explanation for delays on the Merseyrail Northern Line yesterday and again today. I just wondered what it means. Apologies if it's obvious to those of you in the trade!

 

[Big Chris]

It means there is leaf mush on the rails that makes it difficult for trains to accelerate, brake and for track circuits to operate effectively.

 

[bolli]

Doesn't have to be leaf mush especially.
Just means really slippery rails!

 

[trainophile]

Oh right, thank you. I wondered if it was a "leaves on the line" type situation. That explains why at some stations the train I was on was juddering to a halt rather than stopping smoothly, and same again on departure. Tricky one for the drivers I expect.

 

[GB]

Think what "black ice" does to road vehicles and you will not be far off.

 

[barrykas]

Doesn't have to be leaf mush especially.
Just means really slippery rails!

There was a situation on the Northern City Line a few months back, where an overzealous railhead greaser seems to have failed and dumped its entire load in one shot, resulting in a line closure until the resulting mess could be cleaned up.

 

[northwichcat]

The Pacers on the Mid-Cheshire line are performing really badly today. As usual the Sprinters seem to be doing slightly better based on the amount of extra time required.

 

[Southern313]

313's DO NOT like slippery rails. Pulling away from some of our stations noted for poor conditions was made even more frustrating after a drizzle of rain this morning.

 

[A-driver]

313's DO NOT like slippery rails. Pulling away from some of our stations noted for poor conditions was made even more frustrating after a drizzle of rain this morning.

Although the huge advantage of 313s and 455s is that you can hand notch them which means you can get better acceleration in slippy conditions than things like 377s, 365s, 317s etc.

Personally I would take a 313 in slippy season over any other EMU.

 

[DarloRich]

At this time of year poor railhead conditions tend to be caused by fallen leaves, particularly those leaves that come from deciduous tress with big flat leaves, like a horse chestnut.

What happens is that the fallen leaves are blown on to the track or sucked their by the turbulence form passing trains. This in itself isn't a to much of a problem. You should bear in mind a mature deciduous tree can shed up to 50,000 leaves a year!

However, being Britain, it then rains (or a heavy dew comes down) and the leaves get turned into a soggy mushy, muchly, pastelike mess.

A train then comes along, runs over this mess and spreads it out a bit. The friction and thus heat caused by the interaction of the wheel, brakes and the rail then cooks the paste into a hard substance which is stuck to the rail.

The resulting rail coating is very difficult to remove and, i understand, creates conditions for the train driver similar to driving on ice in your car. This obviously means the train cant brake correctly, the trains could then slide and this increases the dangers of passing signals at danger, missing stopping points or even accidents occuring.

An associated problem is that lighter trains we have in service today tend to have disc brakes rather than the old fashioned block brakes. What happens here is that the mulchy mess gets dragged around the wheel as it travels along the rail and ends up coating the wheel and brake. The friction reffered to above then cooks i to the wheel and brake. This means that the train has to come out of service to have the mulch cleaned off.

You also get the problem of wheel flat spots associated with sliding trains caused by poor adhesion. Think about how you hear F1 drivers complaining about tyre damage after they lock up going into a corner. It is a similar situation. This means the train has to be taken out of service for some time for wheel repairs.

Fighting it costs NR abut £30m!

I just wish we were better at explaining the situation to people. Leaves on the line sounds like such a joke but the reality is serious and can have major consequences

 

[sevenhills]

Fighting it costs NR abut £30m!

I just wish we were better at explaining the situation to people. Leaves on the line sounds like such a joke but the reality is serious and can have major consequences

Apart from cutting down any tree in sight, is there a solution to this expensive problem. Fitting cleaners to everyother train, or leave collectors?

 

[sheff'd victoria]

The above has been given as explanation for delays on the Merseyrail Northern Line yesterday and again today. I just wondered what it means. Apologies if it's obvious to those of you in the trade!

The Huddersfield - Sheffield Midland line was suffering yesterday, yet again the trees need cutting back on the section of line from Penistone to Huddersfield.

 

[DarloRich]

Apart from cutting down any tree in sight, is there a solution to this expensive problem. Fitting cleaners to everyother train, or leave collectors?

cutting the trees down would be one option. It does upset people though. It can also de stabilise embankments.

The answer is this:

http://www.flickr.com/photos/darlo2009/6284764440/

The Rail Head Treatment Train. It uses a water canon to blast the leaf mulch off the track and can also add a sandy paste to the track to improve grip. The sand is like a gel and has ferrous metal particles in it.

You have a series of tank units with the water in them loaded into a flat bed wagon: http://www.flickr.com/photos/darlo2009/6218317858/

and a pumping unit, also on a flat bed wagon: http://www.flickr.com/photos/darlo2009/8071715529/

They also come in MPV flavour: http://www.flickr.com/photos/tigertim1950/4432989108/

 

[WestRiding]

then you have the public to contend with when network rail want to fell trees on their land. it is a very worrying time for a signalman when the train insulates itself from the rail, (track circuits) because of the leaf mulch. a train doing 100mph+ that just dissapears off the panel.........

 

[A-driver]

Not only does cutting trees back cause problems with embankments as the routes hold them together to an extent but when NR tried cutting trees back in islington last year to try to reduce the impact during leaf fall they got so many complaints from residents and local petitions etc as people didn't want the trees at the ends of their gardens cut back as they reduce the view and noise from trains.

A bit of a no win situation!

 

[HSTEd]

Could erect clear plastic tents over all railway lines.....

But that would absurdly expensive, would majorly cut down on noise though....

 

[D1009]

Am I right in thinking that this is nothing like the problem it was even a couple of years ago ? I do a lot of travelling by rail ; we are now much of the way through the leaf fall season and although I have had a couple of instances of jerky acceleration, I don't recall experiencing an actual delay which could be attributed to railhead conditions, other than possibly cautious approaches to station stops. I remember a few years ago an HST taking 3 hours to get from Chesterfield to Sheffield, couldn't get any kind of grip. But I guess we didn't spend £30m on it then!

 

[DarloRich]

Am I right in thinking that this is nothing like the problem it was even a couple of years ago ? I do a lot of travelling by rail ; we are now much of the way through the leaf fall season and although I have had a couple of instances of jerky acceleration, I don't recall experiencing an actual delay which could be attributed to railhead conditions, other than possibly cautious approaches to station stops. I remember a few years ago an HST taking 3 hours to get from Chesterfield to Sheffield, couldn't get any kind of grip. But I guess we didn't spend £30m on it then!

I think the approach to dealing with the situation has got better, it has got more coordinated, there is more understanding of how it happens and why. There is also better equipment for dealing with the problem that is deployed more widely.

 

[O L Leigh]

Not only does cutting trees back cause problems with embankments as the routes hold them together to an extent but when NR tried cutting trees back in islington last year to try to reduce the impact during leaf fall they got so many complaints from residents and local petitions etc as people didn't want the trees at the ends of their gardens cut back as they reduce the view and noise from trains.

Unfortunately for them, any tree growing inside the boundary fence or overhanging it is ours. Just as you cannot object to a neighbour felling a tree in his garden, you cannot object when your neighbour happens to be Nitwit Rail.

This year is quite bad thanks to the summer weather we've had. The alternating periods of wet and warm weather have provided ideal growing conditions and not put the vegetation under the normal stresses you get with a long hot summer. Consequently the trees have been green and lush right up to a few weeks ago, meaning lots and lots of leaves coming down about now.

The current mitigation regime seems to work well enough. The combination of railhead treatment, on-train equipment and defensive driving means we don't get quite the same number of overruns or signalling irregularities as we used to. Trains can still pick up delays, but again it's not quite as bad as before. Some TOCs introduce an autumn timetable with a little more slack in it to allow for service recovery if things get particularly naughty.

All that said, the conditions that can really rob a train of grip is light drizzle, and that can happen at any time of the year. But right now, a fine drizzle combined with rail contamination can hole any service below the waterline and then we're all playing catch-up. It really is no joke when that happens.

O L Leigh

 

[DarloRich]

apologies to the TOC's i concentrated on the NR actions in combating the problem. It is a joint effort.

 

[northwichcat]

Unfortunately for them, any tree growing inside the boundary fence or overhanging it is ours. Just as you cannot object to a neighbour felling a tree in his garden, you cannot object when your neighbour happens to be Nitwit Rail.

That's not quite correct.

The overgrowing tree branch does not belong to Network Rail if the tree is planed on land not belong to Network Rail but Network Rail have the right to remove the tree branch from their land. Technically the removed overgrowing tree branch still belongs to the owner of the tree but unless that owner has use for it (such as if they had a shredding machine and would use it for mulch), then the owner is usually happier for Network Rail to turn it in to mulch and to never see it again, then for someone to go round and present the tree branch back to them.

 

[O L Leigh]

Yes I know that.

My point is simply that the residents of Islington (and everywhere else) have no say about what goes on within the railway boundary. Those branches are coming down whether they like it or not.

O L Leigh

 

[Bushy]

Yes I know that.

My point is simply that the residents of Islington (and everywhere else) have no say about what goes on within the railway boundary. Those branches are coming down whether they like it or not.

O L Leigh

NR recently issued a notice to their project staff, consultants and contractors about consultation with neighbours after works to cut back trees and undergrowth in one location had to be cancelled due to objections. It's a complicated issue and like most public bodies NR have to be aware of publicity and reputation.

NR have a statement on their website

Regards

Bushy

 

[HSTEd]

I am pretty sure that if the locals really wanted they could probably get TPOs put on some of these trees and make lots of trouble for NR.

Not worth it in the long run.

 

[O L Leigh]

No doubt these are the same people who moan when the train is late and scoff when we explain the reasons why.

O L Leigh

 

[wolfman]

yet another instance of accountants running the railways and not railwaymen.diesel and electric units were built to keep down track charges,sanders were not built in.(sand was from the steam age)now being built in at increased cost.now we have network rail spending millions trying to beat a problem that would have been avoided if railwaymen had been listened to and not pen pushers.to justify my post all my years as a driver i never experienced problems with bad rail conditions untill the new stock appeared.

 

[Bushy]

yet another instance of accountants running the railways and not railwaymen.diesel and electric units were built to keep down track charges,sanders were not built in.(sand was from the steam age)now being built in at increased cost.now we have network rail spending millions trying to beat a problem that would have been avoided if railwaymen had been listened to and not pen pushers.to justify my post all my years as a driver i never experienced problems with bad rail conditions untill the new stock appeared.

You mean "Leaves on the line" was just an excuse, after all, before modern stock was introduced. As a veteran commuter, I certainly remember it being a problem when they were still running 411s on Kent lines.

Regards

Bushy

 

[HSTEd]

I believe this is where I propose building Shinkansens in all directions as they would all either be in tunnels or on viaducts/embankments and would not suffer so badly from this problem.

 

[30909]

From the end of steam in 1968 for almost 40 years the reduction in lineside vegetation control was obvious and potentially dangerous. As Lengthmen were made redundant, as vegetation and track modernisation did not require their regular – daily - attention; keeping the lineside cleared and maintained reduced the chances of fire in the steam age but was assumed irrelevant in diesel and electric era. Not until the once regularly cut saplings grew into significant trees (20-30 years) was the problem identified. Lineside residents should be shown any pictures of their railway in the 1930s compared with now to see the obvious overgrown nature of the lineside

 

[fsmr]

]

The Rail Head Treatment Train. It uses a water canon to blast the leaf mulch off the track and can also add a sandy paste to the track to improve grip. The sand is like a gel and has ferrous metal particles in it.

As discussed on other threads many times
The mulch and goo from leaves also electrically insulates the wheel from the rail causing the track circuit to fail and hence signalling system as the train cannot be detected unless other means of detction are in use such as axle counters
The "sandite" paste used after jetting contains metal particles (aluminium IIRC) to provide electrical continuity
as well as sand for friction i.e traction or braking