The Planner
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- 15 Apr 2008
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Avanti are funding the non EPS speed increases south of Weaver. Its for the 800s.No, they will do 110mph max, same as the 350s. That’s the backwards step here.
Avanti are funding the non EPS speed increases south of Weaver. Its for the 800s.No, they will do 110mph max, same as the 350s. That’s the backwards step here.
Prior to on train monitoring equipment and TPWS I can imagine running at 150mph+ was probably a semi-regular occurance with the 91s, even if not officially allowed!I believe LNER hold the record for the highest overspeed incident at above 150mph. I can't recall the exact speed it reached but I do remember it happening.
Won't the 807s work to Blackpool?The 805/807s are yet another new development, but given that they won't go north of Weaver Junction, is there nowhere they will run at 125mph using separate timings from Pendolinos or 350s, even Stafford - Wolverhampton?
I've heard stories from the early 90s about 317 drivers who would not apply the brakes until the last tunnel before kings cross station (I think gasworks tunnel?) - supposedly they were doing about 80 until the last tunnel! There is also the story from the early 2000s of a 365 operating the Cambridge Cruiser, with the driver announcing to the passengers that he was going to make up some time, apparently the train lurched to one side and nearly came of the tracks just outside Hitchin.I had back in the 90’s, before data recorders etc, a few runs, with the 91’s, on ECML, hitting speeds of 135-140mph, when making up time on the 3hr 59 mins, London-Edinburgh timings, and there are logs of these sort of runs, done by expert train recorders. I have also had other excessive speed runs, with various traction, one of my most notable, was a 47/8, on a Holyhead-Euston relief, non stop Holyhead-Chester, which managed to, cab ride, from Holyhead to Chester, hitting 99 mph on Anglesey, then continuing at 90mph on to Chester, the driver was a bit of a nutter.
Supposedly, the new MU speed profile on the WCML will go as far as Weaver Jn (for Liverpool).Won't the 807s work to Blackpool?
I think the medals go to the LNER and TPE drivers who reached 140. Plus all the drivers that initially trained 390’s that got them upto 140 as part of the training. Then there’s all the drivers that drive hst’s pre data recorders.
But other than that I guess you won.
In many countries in Europe its simply not possible, or not possible to a significant degree due to various speed monitoring systems.I've seen some interesting explanations about speeding on this thread and it's clear that exceeding rail speed limits is seriously frowned on. (Unlike roads where it just isn't a serious matter, but that's another story!).
Out of interest though, does anyone know whether exceeding rail speed limits is permitted in other countries in mainland Europe?
The semaphore signalling on the Eastern side was the reason that Edinburgh-Polmont remained denoted in the Sectional Appendix as "75mph max (except Glasgow-Edinburgh High Speed Trains - 90mph) until the 1979 revision - presumably it was resignalled to colour lights by then.100mph (possibly plus) in a Class 27 on the Edinburgh-Glasgow push-pull in the 1970s must have been quite entertaining, especially as the east end of the line still had semaphore signalling. A range of such records exist, and I suspect one run I was in myself. One got the feeling the drivers (and inspectors) very much knew what they were doing, and where to do it. No point if on time, as it followed a local in at both ends, but a slightly late start was the incentive.
Nothing supposedly about it, there is no work north of Weaver.Supposedly, the new MU speed profile on the WCML will go as far as Weaver Jn (for Liverpool).
So if 80x work north of there they will do so at current PS speeds (there's not much EPS Weaver Jn-Preston anyway).
The northern WCML MU upgrade may have to wait till HS2 stock arrives.
GPS needs to see several satelites across a wide sky. In a train you only see satelites in a narrow segment of the sky. That degrades their accuracy.Most GPS units are accurate to +/- 1%
If you have a train running at 125mph plus the possible 3mph over, i.e. 128mph, adding 1% on to that gives 129.8mph which is very close to 131mph; so the GPS doesn't even need to be faulty to display 130mph and an extra 1mph is easily explained by the signal getting slightly interefered with - trees are a frequent culprit, as are tall buildings. A reflected GPS signal can confuse the receiving unit.
I thought the electric versions are going to Blackpool?Nothing supposedly about it, there is no work north of Weaver.
Not unless its recently changed.I thought the electric versions are going to Blackpool?
That’s what we got told. But it could just be a railway rumour.Not unless its recently changed.
How is the speed measured? As a ratio of the motor/engine rpm?Digital speedometers are fairly accurate if set up properly. But the set up needs to know the wheel diameter of the wheel set that they are run from.
In theory every time the relevant wheels get reprofiled (on a wheel wheel) the speedo should be recalibrated.
With a wheel of about 880mm (from memory are 890mm when new) taking 4mm off surface will reduce diameter 8mm or about 1%. Obviously at 125mph, 1% is 1.25mph, so if they miss a reprofile or about 10mm surface is lost, could be about 3% out. And logically if initially were 1 or 2% out of true then could get to 5-6mph out of true
It’s measured off axle rotations.How is the speed measured? As a ratio of the motor/engine rpm?
If that's the case, wheel slip will affect the speedo as well.
The driving axle? Or non-driving axles?It’s measured off axle rotations.
Both, if it detects a difference in rotational speeds the WSP will kick in.The driving axle? Or non-driving axles?
Thanks, I just recall that the French TGVs when first introduced, were permitted to exceed speed limits to recoup late running, as they were easy to signal with no non-TGV traffic on the line, and other TGVs usually at least 50 miles away. But I may be wrong.In many countries in Europe its simply not possible, or not possible to a significant degree due to various speed monitoring systems.
Historically, from having read over 120 years worth of Practice and Performance, France, Germany, Switzerland, Austria were all quite strict with observing speeds. Pre-war Germany not so much, but France has a very long history of scrupulous speed restriction observance, they had one of the lowest national speed limits (120km/h, 130 was specially authorised for certain railcars) pre-war while Germany was doing 150/160 and even Belgian was doing 140, with 145 specially authorised for the Ostend Boat Trains behind the famous Type 12s.
Even post-war, while electrics were quickly authorised 140/150 in the 1950s, even by the time Le Capitole was thundering down France at 200kms (from 1967), steam was still restricted to 120. Either way, observance of restrictions appears to have been very tight, the only overspeeds seemingly being down to speedometer under-reading.
By the 1990s most have some form of speed restriction monitoring system or Automatic Train Protection.
I believe that on European high speed lines, higher speeds are permissible which are only used to recover late running, than are used in normal service. I suspect in this country, such a resilient capability which prevents people from missing connections would be dismissed as “gold plating”Thanks, I just recall that the French TGVs when first introduced, were permitted to exceed speed limits to recoup late running, as they were easy to signal with no non-TGV traffic on the line, and other TGVs usually at least 50 miles away. But I may be wrong.
As for the UK, I remember logging many trains in the 1970s at 10% or more over the limit of the loco, it was just an absolutely normal occurrence. Today's incredibly rigid enforcement of rail speed limits often seems more rigid than it really needs to be. Of course there are arguments for being so tightly controlled, but something always seems wrong when our roads are so much more dangerous, and yet so little is done to control our roads. A different argument I guess!
Peter Semmens, who wrote the Practice and Performance column from 1981-2004, wrote a number of articles on the TGV Sud-Est. He undertook a number of cab rides and noted how the technique changed from his initial journeys in the early 80s to later in the decade and when the LGV Atlantique opened.I just recall that the French TGVs when first introduced, were permitted to exceed speed limits to recoup late running, as they were easy to signal with no non-TGV traffic on the line, and other TGVs usually at least 50 miles away. But I may be wrong
Going further back, Mr Semmens predecessor, O. S. Nock, remarked in one how he once broached the subject of overspeeding tolerance with a BR Chief Engineer and he said that 10% was officially tolerated (this was in the 1970s) due to speedometer error for one thing as well as for the fact that all speed restrictions had an inbuilt safety margin in excess of that.As for the UK, I remember logging many trains in the 1970s at 10% or more over the limit of the loco, it was just an absolutely normal occurrence.
I know this has often been touted but I've yet to see ot mentioned in print. To say nothing of the fact it would require the cab signalling to be able to be somehow modified to allow a higher speed in such circumstances, as going over the limit would trigger a brake application. The French TVM will allow a 15km/h margin at high-speeds, the German LZB allows nothing, and indeed in articles references the ICE trains it was noted how the train always kept 2-3km/h below the limit.I believe that on European high speed lines, higher speeds are permissible which are only used to recover late running, than are used in normal service. I suspect in this country, such a resilient capability which prevents people from missing connections would be dismissed as “gold plating”
Is the reading on the speedo averaged from all sensors? If one sensor exceeds 20 percent discrepancy of a nominal wheel circumference the wsp will be active?Both, if it detects a difference in rotational speeds the WSP will kick in.
I believe the Speedo goes off the free axle on the leading end. The averaging of speed probes is just for WSP.Is the reading on the speedo averaged from all sensors? If one sensor exceeds 20 percent discrepancy of a nominal wheel circumference the wsp will be active?
Typically 125 mph or 55.9 m/s would equal nominal 20 wheel revs per second. It all works within milliseconds.
From 1901 onwards, a large number of French locomotives - steam included - were fitted with M. Flaman's patent speed recorders. These were highly accurate devices driven by a spool from one of the axles and recorded on a roll of graph paper not only the loco's speed at any given time, but also the level of driver vigilance by recording the time taken for the driver to react to the various automatic warning devices used over the years. The device was first patented in 1901 and by the outbreak of the first world war about 80% of French locomotives were fitted with them. They were first used by the Nord, Est, Etat and Paris-Lyon-Mediterranee companies, but following nationalisation in 1938 they were quickly adopted as standard by SNCF. The driver would hand in his recording roll(s) with his timesheet at the end of each shift and any overspeed - or loss of time caused by the driver - would result in money being deducted from his pay packet. Conversely however, if the record showed that a driver had managed to recover time following a delay outwith his control, but without exceeding the loco or line speed limits, he would receive a corresponding financial bonus. All this made for a very careful and professional driving technique which was much admired by other railways around the world. Many other railways in different countries subsequently adopted the Flaman recorder, including some in Australia. I believe that the Germanic countries of Northern and Central Europe preferred the Swiss-made Hasler recorders - as also used for many years by CIE/Iarnroid Eireann - but I'm not certain whether these were suitable for use on steam locos. Someone on here will probably know!France has a very long history of scrupulous speed restriction observance,
Isn't that out by a factor of 2? I was taught at primary school that 60mph is 88ft/s. That's 880 ft in 10 s, so 120mph is twice that.Its worth thinking about how GPS operates as well, to follow up on other comments the accuracy dependeds on a number factors, the main one being how much of the sky can be seen. When you get a speed reading, its actually based on the time taken to travel between two points, so the accuracy is going to depend on how accurate those positions are. Usually phone GPS updates once per second, and averages speed over a few readings. Assuming the averaging period is around 10secs then that will equate to roughly 880ft at 120mph.
What year did you leave primary school? We never got taught anything like thatIsn't that out by a factor of 2? I was taught at primary school that 60mph is 88ft/s. That's 880 ft in 10 s, so 120mph is twice that.