|
|
Post by ducatisti on Dec 8, 2011 8:54:20 GMT
following on from the noisy rails thread, A quick question about rail grinding - does the grinder grind to flat or to a domed profile?
IIRC new rail has a (slightly) domed head to it, presumably this will lower rolling resistance?
|
|
|
|
Post by phillw48 on Dec 8, 2011 9:45:15 GMT
It depends on the wheel profile more than the track. There are examples of some stock being barred from Network Rail because of incompatible wheel profile. This suggests that Network rail specifies a particular profile for its track and rail grinding would follow that specification. Experiments were carried out IIRC by British Rail in the 60's into wheel/track interfaces but what resulted I do not know.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 8, 2011 9:57:29 GMT
It depends on the wheel profile more than the track. There are examples of some stock being barred from Network Rail because of incompatible wheel profile. This suggests that Network rail specifies a particular profile for its track and rail grinding would follow that specification. Experiments were carried out IIRC by British Rail in the 60's into wheel/track interfaces but what resulted I do not know. Yes, I know the one you mean. BR were investigating why their wagons kept hunting and derailing on long welded rail because back then everything had one standard whee profile. From then wheel profiles were taken into account and everything had a specific profile. Oh and what stock is banned from NR metals? |
|
|
|
Post by phillw48 on Dec 8, 2011 10:22:06 GMT
IIRC it was some preserved stock were tyre wear although within safety parameters had worn to a profile that was unacceptable. I believe that there was some continental stock although compliant with the British loading gauge was refused for the same reason. Some French ferry vans had their wheel sets changed to comply with the British standards and changed back again on return to the Continent. Strangely enough British profile standards are accepted on the Continent.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 8, 2011 13:49:43 GMT
Mr Railtech they are no longer allowed to transpose rails
|
|
|
|
Post by ducatisti on Dec 8, 2011 15:22:40 GMT
Gauge-cracking? Was the buzzword du jour for a bit post-Hatfield.
I thought all rail wheels coned - are LU wheels more heavily coned?
|
|
|
|
Post by phillw48 on Dec 8, 2011 16:31:08 GMT
LU and mainline stock wheels are all coned. The 'coning' has to fall into certain parameters such as angle and shape. This means that an otherwise perfectly good wheel can be rejected. The purpose of 'coning' is to reduce the flange/rail contact at higher speeds, the coned wheel/tyre will try to 'climb' the outside rail on a curve countering the centrifugal force acting on the vehicle whereas on the wheel on the inside rail drops slightly making the rail vehicle 'lean into the curve' like a cyclist or motorcyclist. In fact this is not really necessary on LU stock as they do not attain the speeds necessary (60mph+). Another wheel profile tested was a concave shape but this was rejected.
|
|
|
|
Post by bassmike on Dec 9, 2011 12:32:43 GMT
I think the coning is at 1:20 ?
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 9, 2011 12:36:53 GMT
Without coning the wheels would only stay on the track by virtue of the flanges and you could only go in a straight line!
XF
|
|
Colin
Advisor
My preserved fire engine!
Posts: 11,346
|
Post by Colin on Dec 9, 2011 15:44:39 GMT
There was something on one of the documentary channels last night, about fast trains.....TGV, Bullets, etc - a Japanese scientist was credited with curing hunting by introducing suspension to bogies following a 60's experiment.
Dunno whether that's factually correct (the Japanese scientist bit) - I suspect it isn't - but I thought it was worth mentioning that coning is only half the solution....
EDIT: don't forget also that the rails are not mounted flat but are angled inwards at the top edges. Points are of course laid flat though!!
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 9, 2011 16:07:21 GMT
This stuff is just fascinating. All normal Joe Soaps, me included, would always have assumed that wheel surface are flat and and all "steering" is done by the flange!
|
|
Colin
Advisor
My preserved fire engine!
Posts: 11,346
|
Post by Colin on Dec 9, 2011 16:47:12 GMT
A quick Google search led me to this link which explains it relatively simply, with a couple of simple images..... |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 9, 2011 21:10:10 GMT
I can vaguely remember a BBC documentary (possibly in the very early days of BBC2) about hunting being the cause of flange wear on a wagon that had derailed and gone into the path of passenger train heading in the opposite direction. Would this have been the Thirsk accident of July 1967? I remember the documentary investigating wheel profiles experiments with different angles of wheel treads. I was only about 8 at the time so this would have been a couple of years after the crash if it was Thirsk.
Despite the loss of life in the accident there was one amusing story to come out of this. Gerry Fiennes was the Eastern Region General Manager at the time and he attended the accident. Once the he had established the cause he authorised the Breakdown Crew to begin recovery. After a few hours the crew had stopped for a breather having made major inroads into clearing up the wreckage. The carraiges and wagons that could be rerailed had been and the rest had been picked up and placed in an adjacent field in orderly rows. It was at this time that a young gent came up to Gerry Fiennes and, surveying the scene of order that the Breakdown Crew had achieved, said "Mr Fiennes? I have a message from the Research Department. It says 'touch nothing until we get there'.....".
|
|
|
|
Post by norbitonflyer on Dec 9, 2011 22:43:13 GMT
I can vaguely remember a BBC documentary (possibly in the very early days of BBC2) about hunting being the cause of flange wear on a wagon that had derailed and gone into the path of passenger train heading in the opposite direction. Would this have been the Thirsk accident of July 1967? That sounds like Thirsk - the wagon was part of a train of cement wagons, and was deraoiled into the path of an express (overtaking, rather than coming the other way) hauled by DP2, the Deltic-lookalike prototype for the Class 50 which was written off in the accident. |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 10, 2011 9:53:09 GMT
Relatively new Harsco RGH20C railgrinder DR79266/276 was sitting shutdown on the through siding at West Ruislip yesterday lunchtime.
I've not been out and about recently apart from yesterday so don't know if it's been there long.
The onward connection to the down siding was rusty so it hadn't just arrived.
Obviously designed with LU in mind it has a beam on the offside front bogie with pipework for a tripcock (which may have been fitted - too far away for a clear view).
Only surface lines,too big for the tubes.
Andy
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 10, 2011 14:11:59 GMT
Relatively new Harsco RGH20C railgrinder DR79266/276 was sitting shutdown on the through siding at West Ruislip yesterday lunchtime. I've not been out and about recently apart from yesterday so don't know if it's been there long. The onward connection to the down siding was rusty so it hadn't just arrived. Obviously designed with LU in mind it has a beam on the offside front bogie with pipework for a tripcock (which may have been fitted - too far away for a clear view). Only surface lines,too big for the tubes. Andy A rail grinder was working between Embankment and South Kensington last night and went back to Lillie Bridge this morning. |
|
|
|
Post by citysig on Dec 10, 2011 16:54:48 GMT
A rail grinder was working between Embankment and South Kensington last night and went back to Lillie Bridge this morning. Thank goodness it went to Lillie Bridge - it took over an hour and a half to go from Ruislip to Embankment ;D |
|
|
|
Post by phillw48 on Dec 10, 2011 19:59:02 GMT
The sight, sound and smell of a railgrinder in action is something to behold.
|
|
|
|
Post by tubeprune on Dec 18, 2011 7:54:07 GMT
A quick Google search led me to this link which explains it relatively simply, with a couple of simple images..... [unashamed plug]and another, even simpler explanation at this link [/unashamed plug]. |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 19, 2011 1:01:30 GMT
Two weeks after I attained the grade of 'Driver' in Oct 1995 (having been a 'passed man' for 22 months) I was booked on the 6V29 night tank train from Furzebrook (Isle of Purbeck) to Hallen Marsh (Bristol). I had a class 60 and, as was common on the Western Main at that time of night, we were crossed to run down the up 'reversible' line from Wantage Road. Approaching the signals before the site of Shrivenham station it was clear that we were not being crossed back onto the down at Bourton but were carrying on the reversible until at least Swindon.
As we passed Shrivenham we noticed a lot of lights on the other side of the two overbridges. My Guard, Dave, commented that he hoped that they were on the down line. They were! About a quarter of a mile past the overbridges the big Speno Railgrinder was in full flow. The shower of sparks looked like Dantes inferno! It was white-hot and clearing our line just under cab level, clearing the embankment and landing in the adjacent field! I stopped the train well short and blew the horn and flashed the red tail lights of the loco to try and alert them. I also rang Swindon box.
'Hello Swindon. This is the Driver of 6V29. I've stopped just west of Bourton crossovers on the up reversible and I'm looking at the Railgrinder in full flow'.
'Yes Driver, and what appears to be the problem?'.
'Well you don't seriously expect me to drive through that shower of sparks with a gas train do you?'!
The air in Swindon turned a deep shade of blue as the signaller realised the potential of what had happened had we not stopped! I had never heard a signaller swear like that before!
'Oh ******* ****! Don't move. ****! I'll try and contact them. ******* ****! Call me back in a couple of minutes.'
I rang him back and he explained that the crew were not answering the 'phone. I mentioned that we could just make out a chap walking behind the machine who appeared to be visually checking the rails after ther grinder had gone over them. Dave took a walk and tapped him on the shoulder. On Daves return he assured me that the crew had been well and truly alerted to the nature of our cargo and would not start the machine until we had passed. I would love to have seen thier faces as we passed them with a train of tanks marked 'Liquefied Petroleum Gas'!
By this time there was a backlog of trains waiting to use the reversible line. We were looped at Swindon and I rang the signaller again. He apologised profusely for the incident. I explained that it wasn't his fault as our respective controls should have twigged what was going on. I then asked where the Railgrinder was working later on.
'It's just packing up and it's moving on to spend the rest of the night working between Wootton Bassett and Hullavington. Do you want to come back via Box?'.
I readily agreed to this. One moment like this in a night was plenty!
I put a report in and recieved a reply to the effect that Railgrinder crews were to be instructed to stop grinding on the approach of any train on adjacent lines. Little victories..........
As a footnote, I mentioned to Dave at the time that there were probably some of our Drivers that would have just gone for it and tried to get past as soon as possible,. He doubted that but, when I saw a couple of weeks later, confirmed that at least four Drivers he had told about this incident would have done just that! Had the LPG in the tanks gone up they would probably still be filling the hole in!!!!!
|
|
