Deepgreen
Established Member
Just out of interest, is that technique based on leaf fall conditions or not? If the latter, how do you deal with leaf fall?Not always. My driving style is such that I use the same technique all year round.
Just out of interest, is that technique based on leaf fall conditions or not? If the latter, how do you deal with leaf fall?Not always. My driving style is such that I use the same technique all year round.
I'm surprised there was no comment on the misinformation that "a Network Rail spokesperson said: "At around 19:00 GMT this evening, the rear carriage of the 17:08 Great Western Railway service from Portsmouth Harbour to Bristol Temple Meads derailed after striking an object on its approach to Salisbury station. "The derailment knocked out all of the signalling in the area". (post 256)
Since this is clearly not what had happened, and caused unneccessary concern about the robustness and safety of the signalling system (which actually performed to specification, the faults were elsewhere), was there ever an investigation as to who gave out this information, and why?
.............. its highly unlikely the railway industry would be able to carry through vegetation removal to the required extent even if it was inclined to try.
I understood that running brake tests were to check that the train brake system performance was satisfactory and not primarily to assess available adhesion. This is stated in clause 54 of the report. The available adhesion at the location of the running brake test is unlikely to be the same at all locations where braking will be required. Sorry I can’t copy the text from the report.That's what running brake tests are for.
The cost of maintaining steam-era trackside conditions would far exceed the savings from avoiding these problems.But the line side vegetation has got into it's current state by budget constraints in the first place. As per normal in the UK, its penny wise, pound foolish.
On the CLC, the passing trains are the biggest controller of line side vegetation. It's an absolutely ridiculous state of affairs, when the consequences aren't just damaged train bodywork, but accidents with serious injuries (or worse).
It's explained in the report that he believed that adhesion would be poor where the tree had fallen earlier, so he made a conscious decision to wait until passing that, for exactly the reason you refer to, but unfortunately left it until 750m past the site of the tree.Shot in the dark here, but is it possible the driver decided to brake later because of local knowledge? I.e. he thought he knew where the poor adhesion would be and wanted to wait until passing it before braking harder on what he perceived to be the section of good adhesion, to avoid sliding from the poor section into the good section?
Railhead adhesion is an intrinsic factor of braking performance, so one of the purposes of running brake tests is to gauge braking performance and how this is affected by the level of adhesion at the time. Clause 54 discusses a running brake test soon after the driver left Waterloo, but there should be nothing stopping a driver carrying out additional running brake tests at any time should they perceive that adhesion may have worsened.I understood that running brake tests were to check that the train brake system performance was satisfactory and not primarily to assess available adhesion. This is stated in clause 54 of the report. The available adhesion at the location of the running brake test is unlikely to be the same at all locations where braking will be required. Sorry I can’t copy the text from the report.
It's very possible, but I don't think defensive driving techniques include the choice to delay braking and then brake hard, even if instinct and/or reasoning prompt it - it's more or less the opposite of what is required.Shot in the dark here, but is it possible the driver decided to brake later because of local knowledge? I.e. he thought he knew where the poor adhesion would be and wanted to wait until passing it before braking harder on what he perceived to be the section of good adhesion, to avoid sliding from the poor section into the good section?
I find it interesting that RAIB have included this image of the change in scene over the last 60 years.
... Lets not lose sight of the fact that this area has a lot more vegetation around it compared to the past. It is lack of maintenance, we can all see vegetation growing out of the brickwork in viaducts.
Blatantly obvious the lack of vegetation management is the primary cause, not mitigated by lack of rail treatment. The rest is all consequences after these.
I use the same technique all year round and never get delay slips. It's the drivers that tear around half the year using too much brake in good conditions that struggle in leaf fall.Fair enough although I think if we used the same technique all year round then the trains would constantly be late!
I am not a driver but I have an interest in understanding the mechanics of wheel/rail adhesion. I can see the logic in this driver waiting until he had passed the area where he understood the poor adhesion to be. It requires a higher level of available adhesion to restart a stationary wheelset than to prevent a rotating wheelset from sliding. Therefore if the driver had commenced braking in step 2 on the area of better adhesion he may have achieved (or at least believed he would achieve) a shorter stopping distance than relying on the older design of WSP (which may not be as effective as more modern systems) with sanding to control the deceleration. This is a judgement that cannot be quantified.Shot in the dark here, but is it possible the driver decided to brake later because of local knowledge? I.e. he thought he knew where the poor adhesion would be and wanted to wait until passing it before braking harder on what he perceived to be the section of good adhesion, to avoid sliding from the poor section into the good section?
I would think, if they still won't cut them down, this may be criminal negligence, certainly mismanagement. If DfT won't fund vegetation management, then they should be prosecuted. Putting cost cutting over safety is never right, whether it is rail, road, air or health.
I use the same technique all year round and never get delay slips. It's the drivers that tear around half the year using too much brake in good conditions that struggle in leaf fall.
Your first sentence is spot on, your second paragraph diminishes your opinion somewhat. Drivers are a small cog in the bigger wheel and the majority of drivers are of the same opinion.Or just listen to the colleagues who told him on the day. It’s in the report.
I know the view is - particularly in the driver grade - that drivers are more important than everyone else. But they are not above criticism.
I drive cautiously throughout the year and there’s plenty of padding within the timetable to be on time.Fair enough although I think if we used the same technique all year round then the trains would constantly be late!
Who will pay for the many thousands of new staff that will be required?Technical solutions are not needed, just cut the trees down and then, keep them from re-growing. This is a 50 year long literally growing problem, caused by first BR giving up lineside maintenance as soon as steam finished and then Railtrack and NR doing even more nothing. Paul Clifton on BBC South tonight, quite rightly highlighted the tree growth problem and used the Warship picture on screen to compare with a scene from today. He pointedly said that the trees are still there 2 years after the crash and that NR when contacted, refused to comment.
The reality is that benefit cost ratio analysis exists precisely because safety is not infinitely valuable.Putting cost cutting over safety is never right, whether it is rail, road, air or health.
Genuine question, how is it possible to drive the same all year round and still keep to time when they put extra padding in the timetable from around October time specifically for leaf fall?I use the same technique all year round and never get delay slips. It's the drivers that tear around half the year using too much brake in good conditions that struggle in leaf fall.
Keep in mind that during the growing season, hundreds of signals get reported because drivers find that they become or are becoming obscured by vegetation. In some areas, the vegetation is intertwined around the signal structure…Who will pay for the many thousands of new staff that will be required?
Who will pay for the massive disruption from the line closures that will be required, for the rest of time, to allow lineside vegetation to be taken back to the stema era?
This is not the 1920s, we do not have a vast underclass of cheap Irish labourers to throw at the problem. And modern safety culture will not tolerate the inevitable increase in workforce fatalities from working next to an open railway - so the railway will be forced to adopt a lower availability maintenance scheme with the huge attendant costs.
The reality is that benefit cost ratio analysis exists precisely because safety is not infinitely valuable.
If it was, industrial society simply could not exist.
The real answer here is better sanding equipment, magnetic track brakes and eddy current brakes. Not trying to spend billions a year on a huge increase in staffing and reduction in sustainable railway traffic.
And how long would it take for the rolling stock to be retrofitted with such technologies, let alone the time to research and develop them?The real answer here is better sanding equipment, magnetic track brakes and eddy current brakes. Not trying to spend billions a year on a huge increase in staffing and reduction in sustainable railway traffic.
Genuine question, how is it possible to drive the same all year round and still keep to time when they put extra padding in the timetable from around October time specifically for leaf fall?
That is my understanding. Once the wheels are locked up it takes an age to get them rotating again and then able to apply the brake - that's my understanding.Shot in the dark here, but is it possible the driver decided to brake later because of local knowledge? I.e. he thought he knew where the poor adhesion would be and wanted to wait until passing it before braking harder on what he perceived to be the section of good adhesion, to avoid sliding from the poor section into the good section?
But is the running brake test more to test the trains brakes ?. Its not really to test the rail conditions which vary from place to place ?.Railhead adhesion is an intrinsic factor of braking performance, so one of the purposes of running brake tests is to gauge braking performance and how this is affected by the level of adhesion at the time. Clause 54 discusses a running brake test soon after the driver left Waterloo, but there should be nothing stopping a driver carrying out additional running brake tests at any time should they perceive that adhesion may have worsened.
Good question - answered later as NO.Has or had a lot more vegetation around it compared to the past ? i.e. During almost two years has the vegetation been significantly cut back not just above the tunnel portal but along the approaches ?
I breath of realism. We are talking about humans. This was a very experienced driver (both traction and route).Braking pretty conservatively is the default drivers are trained to these days and should, with decent RHTT and modern brakes, allow a reasonably timely performance all year round, especially if an additional margin is added to the timetable during leaf fall*.
As drivers I’m sure we have all taken the odd risk and slid into stations too quickly during leaf fall in full service, hoping the brake will bite, and wondering “how will this look on the download if I slip through”. Once you’ve scared yourself once or twice, you become conservative…
Ultimately the timetable isn’t even a consideration when it comes to matters of safety, or when it comes to maintaining a marketable CV as a qualified train driver!
Taking silly risks also makes precious little difference to the timetable: I was on a noticeably conservatively driven and early braked SE Networker earlier this evening (I say that as someone who drove them myself for a few years), and noted from RTT that the time lost was minimal, in the scheme of the various built in allowances etc.
*As an aside, it’s notably late this year! Most leaves are still on the trees due to the unusually mild start to autumn.
I totally agree.This problem has been in the making for decades and it is coming home to roost.
Braking pretty conservatively is the default drivers are trained to these days and should, with decent RHTT and modern brakes, allow a reasonably timely performance all year round, especially if an additional margin is added to the timetable during leaf fall*.
As drivers I’m sure we have all taken the odd risk and slid into stations too quickly during leaf fall in full service, hoping the brake will bite, and wondering “how will this look on the download if I slip through”. Once you’ve scared yourself once or twice, you become conservative…
Ultimately the timetable isn’t even a consideration when it comes to matters of safety, or when it comes to maintaining a marketable CV as a qualified train driver!
Taking silly risks also makes precious little difference to the timetable: I was on a noticeably conservatively driven and early braked SE Networker earlier this evening (I say that as someone who drove them myself for a few years), and noted from RTT that the time lost was minimal, in the scheme of the various built in allowances etc.
*As an aside, it’s notably late this year! Most leaves are still on the trees due to the unusually mild start to autumn.
Lest we forget. Whatever the cause - bad things happen AND it was probably the design of the coaches in the train that resulted in less casualties. So there is progress.No matter how many times I read this report, I still can’t make much sense of what this driver was doing. I find it bordering on incredulous that a driver would be scouring the line (at nearly 90 mph) in the pitch dark for a fallen tree to use as a braking marker, when he had a perfectly good braking marker in the former of the double yellow aspect, even if this meant the red aspect was heavily overbraked.
I suspect this is going to be added to the list of incidents where we we will probably never know the true cause. It would neatly fit in to the box of commonly seen caution aspect, no need to react immediately (especially in this case with the extra distance), lose concentration (in this case possibly wondering about the fallen tree), and then the brown stuff moment - except in this case the driver still applied light braking. To me the whole thing made little sense in the first version of the report, and it still doesn’t.