spark001uk
Established Member
- Joined
- 20 Aug 2010
- Messages
- 2,326
It's not just the height though is it, it's the curves, as pointed out recently (again).
Hence, why I included the lengths.It's not just the height though is it, it's the curves, as pointed out recently (again).
Ok. It's titled height comparison, so I thought that's what you were highlighting.Hence, why I included the lengths.
Sorry, should made it clearer, that it was both.Ok. It's titled height comparison, so I thought that's what you were highlighting.
We have computers for this kind of thing now. Take a 3D laser scan of the tunnel, and a 3D laser scan of the train in the depot. Put the two together in the computer and it'll tell you down to a fraction of a millimetre what the clearance is. Much simpler, much safer, and much cheaper if the answer's not what you were hoping for! Just make sure you've cleared any shrubbery away from the tunnel mouth when the laser starts...I wonder if it's worth, or even possible, to attach a single carriage to a road railer or other vehicle, and push the carriage through to prove it works.
Make sure there are press photographers on Esplanade platform to take photos of the undamaged carriage.
Obviously, an unpublicised dress rehearsal in the early hours of a dark night might be a good idea, just in case..
(I remember when BR showed off a wheelchair accessible coach, only to find the wheelchair didn't fit).
It's been suggested that the power supply - though undeniably flaky - could still have allowed longer trains if sufficient units were available, certainly the comments by Chris Garnett about voltage drop were debunked.
I've not seen much evidence of 6-car trains, but it seems the spare driving motor made 3TIS+3TIS+DM quite a regular sight.
I'm not sure 3-set trains ever did operate. In any case, it would have caused problems at Lake, where the platform is only 5 cars long (most 485/486 trains operated in 5 car sets in their last few years).
There were far less than 43 485/6 cars left by the time the 483s appeared. The fleet was probably not much more than 20 cars by that time.I read somewhere late last year that Mark Hopwood had asked if a 4-car set could be run on the last weekend. Once 008 was sidelined there was no possibility as 007 could not run in multiple.
Back to the 485 / 486 sets indeed over time numerous combinations. While it did happen the 3TIS sets were not intended to run alone e.g. linked photo 1 & linked photo 2 from this website page .
In asking about 6-car trains I was thinking of the 483's though. The answer may well be no based on this reply
A 4-car 483 would nominally have the same capacity as a 5-car 485/486 with two Driving motors and three trailers. The fact that an active fleet of eighteen 483 cars replaced fourty-three 485/486's shows the decline in demand in just over twenty years. Now thirty years later ten 484 cars are replacing the 483's.
We have computers for this kind of thing now. Take a 3D laser scan of the tunnel, and a 3D laser scan of the train in the depot. Put the two together in the computer and it'll tell you down to a fraction of a millimetre what the clearance is. Much simpler, much safer, and much cheaper if the answer's not what you were hoping for! Just make sure you've cleared any shrubbery away from the tunnel mouth when the laser starts...
In asking about 6-car trains I was thinking of the 483's though. The answer may well be no based on this reply
The gauging systems I've seen results from account for the kinematic envelope and profile. That and a table of tolerance applied by the engineer. The computer will only output the clearances - it doesn't specify the speeds, that's the engineers job.While that's true for something static, gauging must also allow for trains to move around especially when negotiating sharp curves at speed on ballasted track like Esplanade Tunnel - as modern gauging has a reputation for being quite conservative one wonders if this has tripped up Vivarail.
The gauging systems I've seen results from account for the kinematic envelope and profile. That and a table of tolerance applied by the engineer. The computer will only output the clearances - it doesn't specify the speeds, that's the engineers job.
Indeed - but there's nothing you'd get from pushing a unit through at less than walking you won't get from a computer, which is what my response was saying. If you wanted to test the kinematic profile with a live unit, you'd need to arrange for it to go through at linespeed. And given it's a single bore tunnel, good luck convincing an engineer to stand in front of the unit with a torch to check how close it gets!Of course, but it's those tolerances that allow for the vehicle moving around and the data/assumptions behind them which could be the difference in this case.
I would have thought it would be better value for money to just pay a surveyor to do it from a tripod-mounted scanner.I was half expecting they'd have put a RILA scanner or similar through the tunnel at some point, but I'm not sure (in the RILA's case at least) if it would mount onto a 483? Fugro do say the latest device will fit "any passenger train", but I fear they may not have necessarily had 83yr old tube stock in mind.!
I was thinking along the lines of the kinematics being measured from a moving unit.I would have thought it would be better value for money to just pay a surveyor to do it from a tripod-mounted scanner.
20, then at St Johns road goes up to 45 I think.I was thinking along the lines of the kinematics being measured from a moving unit.
What's the current line speed through the tunnel?
Indeed - but there's nothing you'd get from pushing a unit through at less than walking you won't get from a computer, which is what my response was saying. If you wanted to test the kinematic profile with a live unit, you'd need to arrange for it to go through at linespeed. And given it's a single bore tunnel, good luck convincing an engineer to stand in front of the unit with a torch to check how close it gets!
I was half expecting they'd have put a RILA scanner or similar through the tunnel at some point, but I'm not sure (in the RILA's case at least) if it would mount onto a 483? Fugro do say the latest device will fit "any passenger train", but I fear they may not have necessarily had 83yr old tube stock in mind.!
My bold. This suggests the fault lies with the engineers, not the software.True, though modern gauging software has been criticised for being more conservative than more traditional methods - there was a good article in Rail Engineer a few years back:
"However, when (Network Rail’s) National Gauging Database was introduced, it became clear that some rolling stock was running in locations where clearances were indicated to be sub-standard or foul. The accident free history of the running of such rolling stock indicated that this was not likely to be a true clearance issue, but one of conservatism in the calculations. More detailed examination revealed the origin of such conservatism as being in the tolerances that are routinely applied as part of the gauging process."
I wonder if the sidings and P3 can be independent switched on or off?Have they turned the power back on at Ryde? 001 has been seen moving outside Ryde works on the siding where 009 and 008(?) had been stabled.
https://www.facebook.com/IslandEcho/videos/243398137438122/
It could also be something to do with DC switchgear they are replacing (or even by now replaced) at Ryde St Johns.I wonder if the sidings and P3 can be independent switched on or off?
Did you see the ridiculous comments? It’s allegedly being “pulled along”...
I did. And I thought I'd seen enough stupid comments on the internet this week (bangs head).I wonder if the sidings and P3 can be independent switched on or off?
Did you see the ridiculous comments? It’s allegedly being “pulled along”...
It was fitted with batteries in the saloon for initial tests on the mainland, so possibly.I did. And I thought I'd seen enough stupid comments on the internet this week (bangs head).
Could it also be moving under battery power?
No need to fully charge the train line and air auxiliaries as on 483s, just keys in, radio setup, check signal and go!I hope Vivarail have got the dwell times sorted with these, realtimestrains shows the new half hourly service from May 16th and they only get 4mins at Pier Head...
I hope Vivarail have got the dwell times sorted with these, realtimestrains shows the new half hourly service from May 16th and they only get 4mins at Pier Head...