Poor Rail Head Conditions

[28XX]

What on earth are the 'poor rail head conditions' we were told about which caused the 07:57 Worcester Shrub Hill to New Street to be re-routed via Camp Hill this morning?

 

Sounds like another bit of p.c to me...

[johnb]

It's very probably pc speak for "Leaves on the line."

 

 

What on earth are the 'poor rail head conditions' we were told about which caused the 07:57 Worcester Shrub Hill to New Street to be re-routed via Camp Hill this morning?

 

Sounds like another bit of p.c to me...

[43110andyb]

Sounds silly but it can be quite dangerous. Poor braking ability on slippery rail and possible problems with track circuit operation can occur. A minor shunt involving two passenger trains in Darlington not long ago was suspected poor rail head conditions.

[Guest stuartp]

It is leaves on the line. Leaves get crushed between the wheel and railhead (a train makes a very effective power press) and the residue has three effects:

 

1. It decreases friction between wheel and rail thus reducing accelleration by causing wheelspin, which increases journey times and damages wheel and rail,

2. The same effect reduces brake effectiveness by causing wheel slide which causes flats, requiring earlier and lighter braking which also increases journey times,

3. It forms an electrically insulating layer which causes mayhem with track circuits, including making trains disappear from them.

 

There are work-arounds for all these (Sandite/RHTTs, track circuit actuators, axle counters etc etc) but some are more effective than others depending on the exact conditions.

 

More info here: http://www.awg-rail.co.uk/pages/about-awg.html

[Fat Controller]

Exactly what it says- the torrential rain and winds of the last few days have knocked a lot of leaves off the trees. This sounds harmless enough, until you experience what they are like when they've been crushed- they're bad enough when you encounter them on the road, but when they've had a few passes with rail wheels, which concentrate five to ten tons on to an area the size of a five-pence piece, they have about the same coefficient of friction as a piece of Teflon. The result is that when you accelerate, the wheels spin, and if you brake, the wheels lock. Network Rail (and all their continental equivalents) have all sorts of gizmos to remove the material, but they can't cover everywhere all the time- try looking for 'RHTT', Rail Head Treatment Train or Sandite to see some of the measures used. Once drivers have reported difficult conditions on a section of track, Network Rail are obliged to take steps to mitigate the effects, by either reducing speeds or reducing/diverting services- if they did not, and there was an accident, they would be hammered both legally and in the press.

As I say, the problem is not confined to the UK (as one might think on reading the press)- friends who work at SNCF tell me their depots are filled with stock requiring wheel-turning once the leaves fall, whilst I have heard similar stories from SNCB/NMBS and DB.

Should you doubt the qualities of compacted leaves, try applying a full emergency stop in your car on them, though make sure there's no-one else about, and that you've a change of underwear....

Brian

[Glorious NSE]

This RAIB report gives an insight into how scary the braking side of the equation can get...

http://www.raib.gov.uk/cms_resources.cfm?file=/070108_R252006_Part%201%20Autumn%20Adhesion.pdf

[craigwelsh]

Network Rail were quoted in Steam Railway as getting caught out by the leaf fall season coming early this year.

 

The RHTT unit arrangement passed my flat about 2am last night and i'd guess the rail really needed it there even though Network Rail had made a lot of effort to cut back trees in the area.

[Fat Controller]

Network Rail were quoted in Steam Railway as getting caught out by the leaf fall season coming early this year.

 

The RHTT unit arrangement passed my flat about 2am last night and i'd guess the rail really needed it there even though Network Rail had made a lot of effort to cut back trees in the area.

The RHTTs have been running for a couple of weeks already, as photos posted on this site show- however, leaf fall this weekend has been quite spectacular. I finished my first night shift on Saturday morning at 05:30- on the way to work at 21:00 on Friday, the road was almost clear, but on the way back, it was blanketed with leaves, and was 'interesting' to drive on. I was glad that all the idiots who belt from Canterbury to Folkestone/Ankh Morpokh for the nightlife at weekends were tucked up in bed, as most of them seem to struggle to control their cars under normal conditions.

Brian

I've just looked at the SNCF web-site, where I found the following:-

'

En raison d??™un probl??me d??™adh?©rence des roues sur le rail pr?©s de Roanne li?© ?  la pr?©sence de feuilles mortes sur les voies, le train Intercit?©s 4504/5 Lyon 09h04 / Tours 14h09, enregistre un retard de 55 min.'

'Because of adhesion problems between the wheels and the rails near Roanne, due to the presence of dead leaves on the track, Intercity 4504/5 (Lyon 09:04/Tours 14:09)is shown as running +55 minutes'

[Mallard60022]

The RHTTs have been running for a couple of weeks already, as photos posted on this site show- however, leaf fall this weekend has been quite spectacular. I finished my first night shift on Saturday morning at 05:30- on the way to work at 21:00 on Friday, the road was almost clear, but on the way back, it was blanketed with leaves, and was 'interesting' to drive on. I was glad that all the idiots who belt from Canterbury to Folkestone/Ankh Morpokh for the nightlife at weekends were tucked up in bed, as most of them seem to struggle to control their cars under normal conditions.

Brian

I've just looked at the SNCF web-site, where I found the following:-

'

En raison d??™un probl??me d??™adh?©rence des roues sur le rail pr?©s de Roanne li?© ?  la pr?©sence de feuilles mortes sur les voies, le train Intercit?©s 4504/5 Lyon 09h04 / Tours 14h09, enregistre un retard de 55 min.'

'Because of adhesion problems between the wheels and the rails near Roanne, due to the presence of dead leaves on the track, Intercity 4504/5 (Lyon 09:04/Tours 14:09)is shown as running +55 minutes'

 

I think more announcements should be made in French; it seems, from the item quoted, very friendly and would give 'customers' something to think about as they await their late running bog cart.

Bon. Msr Letrack

[Fat Controller]

I think more announcements should be made in French; it seems, from the item quoted, very friendly and would give 'customers' something to think about as they await their late running bog cart.

Bon. Msr Letrack

There was a conductor on Central Trains who used to give bi-lingual announcements in a strong Caribbean accent...

French is a great language for making excuses in- I use it a lot for that. However, the reasons for a platform change, for example, can take so long to relate that the train has left before you realise what the message was about. My 19year old French god-daughter travelled by train from Ashford to Gourock, thence to Crewe, and finally back to Ashford over the summer- she said the UK announcements were much easier to follow than SNCF ones.

[Mallard60022]

There was a conductor on Central Trains who used to give bi-lingual announcements in a strong Caribbean accent...

French is a great language for making excuses in- I use it a lot for that. However, the reasons for a platform change, for example, can take so long to relate that the train has left before you realise what the message was about. My 19year old French god-daughter travelled by train from Ashford to Gourock, thence to Crewe, and finally back to Ashford over the summer- she said the UK announcements were much easier to follow than SNCF ones.

Well, I can sympathise with that. Once, at Poznan in Poland, I was waiting for my return steam hauled train to Wolsztyn. The weather was freezing fog and they had to do a platform change. There was, I assume, some sort of announcement but I only realised what was going on when the Ol49 pulled into a platform seemingly miles away and I had to try to run (if you saw me you'd understand the 'try') to get to it. Being Poland I could have probably just rushed across all the intervening tracks, BUT I'M BRITISH and needed to abide by the rules.

I did get to it (just) and tumbled into a lovely warm coach just as it moved off. I was actually supposed to be driving it but decided to stay in the coach as the weather was so b****y cold and you could not see more than a few yards! Think the crew were probably grateful to be left to it and not have to supervise some plonker that didn't know what he was doing! Incidentally, they still drove like loonies and we were ahead of time at Wolsztyn despite all those station stops in the middle of nowhere.

Sincerely, C.O. Wardycustard.

[Edwin_m]

In Germany you probably find nobody can understand the announcement until they get to the important verb at the end...

[The Stationmaster]

In Germany you probably find nobody can understand the announcement until they get to the important verb at the end...

 

Some years back I was making my way one Sunday morning from Berne to Frankfurt (thence connection via Brussels to London) only to hear a very complicated announcement in German followed by one in French (the train was still in Switzerland) which boiled down to 'this train is being diverted due to engineering work' - as I only had a 7 minute connection in Frankfurt I really didn't care what language it was in, both were equally worrying (especially when the train left Basle DB 10 minutes late).

 

But I did make the connection

[PaulRhB]

This RAIB report gives an insight into how scary the braking side of the equation can get...

http://www.raib.gov....%20Adhesion.pdf

 

Go to page 9 items 31 and 32, this is the Signalman and Driver earning their money big time. Quick response by the driver, no panic, a precise emergency call and then a Signalman who put that information and his/her experience to full use keeping everyone safe.

see also items 46 & 47

Did you notice though that the Signalman was actually praised for thinking on his feet and telling the train in front to keep going, I remember this happening and a technical break of the rules actually ensured safety.

 

There are a multitude of reasons why leaf fall is such a big problem now, lightweight units with disc rather than tread brakes are often blamed but that's not the whole picture, lack of tread brakes is more likely to cause false clears on the track circuits due to build up on the units wheels. The very high passenger train frequency means that the leaves are getting crushed without many trains going over that are heavy enough to grind through the compacted mulch.

Despite the urban myths other countries do suffer exactly the same problem especially with commuter trains, see this months Trains magazine covering the problems in the USA.

The MPV's and RHTT's do work but it is very difficult to path them between all the other services without them also adding to delays.

I worked 3 months in the Wessex adhesion control two years in a row a few years back when we first got the MPV's and I can tell you from experience that re-diagramming them each night to avoid all the engineering blocks and still cover all the sites is damn hard work. I frequently relied on the good attitude of MPV crews and Signalboxes to get the circuits done ready for the morning rush.

I know it's annoying that you are delayed but at least they play it safe.

[dave1905]

I take it then that UK engines don't have sand?

[iploffy]

It is leaves on the line. Leaves get crushed between the wheel and railhead (a train makes a very effective power press) and the residue has three effects:

 

1. It decreases friction between wheel and rail thus reducing accelleration by causing wheelspin, which increases journey times and damages wheel and rail,

2. The same effect reduces brake effectiveness by causing wheel slide which causes flats, requiring earlier and lighter braking which also increases journey times,

3. It forms an electrically insulating layer which causes mayhem with track circuits, including making trains disappear from them.

 

There are work-arounds for all these (Sandite/RHTTs, track circuit actuators, axle counters etc etc) but some are more effective than others depending on the exact conditions.

 

More info here: http://www.awg-rail..../about-awg.html

 

 

i can vouch for all of this many is the time we slid into Coventry and then wheel slipped out

[PaulRhB]

I take it then that UK engines don't have sand?

 

 

Locos do but many units, the main problem trains, only have it automatically applied rather than manually controlled. Some units also had one shot emergency sanders but some TOCs have removed them as they weren't used much and didn't justify the cost. Fill in your own response!

[Edwin_m]

I take it then that UK engines don't have sand?

 

The report linked by Glorious is one of three. Two covered specific incidents and the third one was a wider investigation into the adhesion problem which at the time (2005) seemed to be getting worse. It confirms that the vast majority of multiple units now have automatic continuous sanders although a few retain the one-shot variety or are not fitted. Many locos also have sand but it is more for traction than for braking.

[Glorious NSE]

Go to page 9 items 31 and 32, this is the Signalman and Driver earning their money big time. Quick response by the driver, no panic, a precise emergency call and then a Signalman who put that information and his/her experience to full use keeping everyone safe.

see also items 46 & 47

Did you notice though that the Signalman was actually praised for thinking on his feet and telling the train in front to keep going, I remember this happening and a technical break of the rules actually ensured safety.

 

Yes it's a fascinating report to read through, and I totally agree about those guys earning their money that day.

 

Ref sanders, my impression is that BR didn't hold with the idea (cost cutting reasons??) - at least outside of freight loco's - for example class 47's (hundreds of which were freight loco's) didn't have them at all, class 50's were built with them fitted but BR removed the equipment on refurbishment and so on.

 

Somewhere or other i've some shots (and annoyingly I can't find them at the moment) from Slough of them cutting the station canopy away from a Thames Turbo (165) that had alledgedly slid all the way from Dolphin Jcn to the buffer stops in the bay platform there, and still hit with enough force to put the first coach and a half of the 3 car unit through a curtain wall and across the concourse - I believe that accident was one of the driving forces for BR introducing the "one shot" sander for sprinters.

[Oldddudders]

The base cause of all this serious grief is the abolition of the local P Way gang - and, to a certain extent, the demise of steam. In "the good old days" there were guys aplenty to maintain the track and keep local vegetation under control. The odd spark causing a fire helped that cause, but seldom made the headlines because the guys were available to control it, and to extinguish it before it became a danger. Come the '60s, costs of bods were soaring - and mechanised track maintenance and CWR became the fashion, with all sorts of benefits, not least in maintenance costs. So, with the guys now in short supply, and road vehicles now the order of the day for accessing today's site - guess what didn't get done? When the 1.4.94 split of Railtrack and BR was imminent, there was a sudden panic that the main contract for BRIS to maintain Railtrack's infrastructure didn't contain a clause for vegetation clearance.... There is pictorial evidence everywhere of trees where once were bushes, thick woodland in place of the odd sapling. Environmentalists - and local population - love them for their sound- and sight-screening. Come the Autumn and the railway reaps the reward as well-depicted in this thread.

[Edwin_m]

I was project manager at BR Research for fitting one-shot sanders to the 159s, the first fleet to be fitted. They were certainly effective as we found out on a special test with the first ECS of the day on a foggy morning somewhere out towards Axminster. Of course by definition you only had "one shot" (someone came up with a two-shot version IIRC) so the continuous sander is a better bet. We analysed the OTMR for several incidents, one of which would have prevented an overrun of 1000m or so if (which we had no way of knowing) the adhesion had stayed as poor as it was when the driver hit the button.

 

This was autumn 1995 and SW Trains was either about to be privatised or just had been, so while BR kicked it off the privatised TOCs to their credit were resonsible for following through. Railtrack was however nervous about the effect on track circuits and the maintenance consequences of dumping sand on the track, and the RAIB report shows that this concern strongly influenced later developments.

[Oldddudders]

Railtrack was however nervous about the effect on track circuits and the maintenance consequences of dumping sand on the track, and the RAIB report shows that this concern strongly influenced later developments.

Don't I recall a Class 59 "disappearing" at Botley in the early days, when the auto sanders did their stuff? Having once stood in a signalbox and watched a train disappear - it cleared one track circuit several seconds before occupying the next, it is not the most comforting of experiences.

[Edwin_m]

Don't I recall a Class 59 "disappearing" at Botley in the early days, when the auto sanders did their stuff? Having once stood in a signalbox and watched a train disappear - it cleared one track circuit several seconds before occupying the next, it is not the most comforting of experiences.

 

Yes, that was the panic a few years before. Don't recall the class 59 incident but plenty of 158s were vanishing around 1990. I've heard it said that if the autumn is wet the track circuits work fine but there are adhesion problems, and if it is dry it is the other way round.

[PaulRhB]

Don't I recall a Class 59 "disappearing" at Botley in the early days, when the auto sanders did their stuff? Having once stood in a signalbox and watched a train disappear - it cleared one track circuit several seconds before occupying the next, it is not the most comforting of experiences.

 

 

Yes Ian you do remember correctly they had to be worked with a special headcode on Wessex as a result if running light loco, 0Y59. This requirement was removed a couple of years back as they had modified the sanding equipment. Funnily enough there have been instances of light loco 66's vanishing as the steering bogies wear a concave groove in the wheels meaning that they can be riding on the dirty outer head of the rail rather than the shiny top. The 66's have to visit the wheel lathe more frequently to prevent this.

There is a requirement for drivers to tell the signalman immediately if they use the one shot sand as it tends to be in a big pile as it is still deploying as the train stops and the train can disappear on its own sand.

The SWT 159's no longer have one shot equipment.

[dave1905]

It just suprised me that it would be enough of a problem that anybody would shut down a line for leaves on the rail. Here in the US, a major class one railroad might have one or two stalls a month in season on ruling grades where the trains are right on their horsepower (13,000 tons and 8800 hp), but other than that its not a common problem and I've never heard of having to clean off the rails or shutting down a line for leaves. We did have to plow seaweed off a coastal line in Texas after a hurricane storm surge. 8-)

 

Of course you probably don't have the problems with wind. We have to shut down some lines in Wyoming when they get winds over 60-70 mph (out there a 30 mph wind is a "light breeze"). Those 18-20 ft tall cars tend to blow over in a 70 mph crosswind if they are moving.