Turtle
Member
- Joined
- 18 Mar 2013
- Messages
- 301
And no coffee.Nope. Still done manually.
And a meeting sans biscuits for someone!
And no coffee.Nope. Still done manually.
And a meeting sans biscuits for someone!
In most cases the changeover point is where it is for a good reason - complexity of extending 3rd rail further back for example.Surely that's fixed by moving the changeover point back a few train lengths, no?
Dropping the pan through a neutral section to change wire height/tension/current/voltage though is different to switching between third rail and OLE. For one thing, if you're going from HS1 to ET the wire rises. I presume that in both directions there is no break in the wire and there is a gradient in the contact wire that meets the standards (noting that wire height goes up and down for things like level crossings and bridges all the time), and so forgetting to lower the pan would be unlikely to result in catastrophic damage.Eurostars change from 25kV HSL to 25kV ET (and vice versa) on the move nesr Westenhanger. This involves lowering and raising the pan. Similar process in France and in Belgium.
The third rail goes where it does for the former 3rd rail depot. AIUI the Westway sliproads as they are are currently either too low or would force a too steep wire gradient, although this problem is solvable - studies have looked at extending the wires to Shepherd's Bush station before, and other papers have mentioned Kensington as a future OLE changeover point.It seems set up to create consequences - the wires carry on to within 50m of a bridge for the pantograph to hit.
Are the Westway sliproads really too low for the wires? An extension of 60m would get the pantograph under the bridges and then it has 400m to go overheight and the ADD to drop it.
Not sure why wire gradient would be an issue - what does it need to be high for to the north of the Westway.. AIUI the Westway sliproads as they are are currently either too low or would force a too steep wire gradient, although this problem is solvable - studies have looked at extending the wires to Shepherd's Bush station before, and other papers have mentioned Kensington as a future OLE changeover point.
When I last looked at extending the wires, it gave a tiny benefit to passenger trains and a reasonable benefit to freight but only if the freight could still change on the move.
Unnecessarily complicated. Camera linked to a signal is all that's required.
The lines are reversible here and any tripcock device (fitted on the bottom of the train) would need to be linked to the pantograph systems on the top of the train with a pipe capable of dumping the pressure quickly enough. Also the tripcock would need to be located in such a place that it won't be struck inadvertently by any other trackside equipment on any other part of the network. And the stop block would need to be located not to knock the shoes off the unit at the same time. Costs of design are quickly starting to add up, then there's fitting and then maintenance.Still unnecessarily complicated and fancy? The life-or-death safety critical nature of signalling seems to mean that tinkering with it in any way opens a hugely expensive and protracted can of worms, justifiably so perhaps.
Why not something as simple as a tripcock thing akin to those used on the tube to deal with SPADs then? The locations where this happens all seem to be low speed so it can't be the practicalities of high velocities. Doesn't even need to go up and down unless the lines are reversible etc, it could just sit there with no power supply needed. Clouts something correctly located under any train with a pantograph, and drops it. Or even just a fixed magnet type thing. Doesn't have to be 100% foolproof to drastically reduce the risk from low to ~0.
No doubt there must be a massive long list of reasons otherwise someone would have thought of it within 10 seconds the first time the question was posed.
The argument about false recognition was about wrong-side failure in a device linked to the signalling system. A separate indicator designed to trigger a 'Check Pantograph' warning that doesn't impact the signalling system would not need to be so critically fail-safe but false negatives are a far bigger concern than false positives.Camera linked to an indicator that isn't part of the signalling system though - why not? Just needs to flash up a visual "You've got your pantograph up you ****" type warning. The argument that image recognition is imperfect seems like "perfection being the enemy of progress", especially given recent strides in AI type machine learning that could be applied to refine it over time. What's the worst thing that can happen? A few unnecessary emergency stops due to false positives? It seems unlikely that the false positive and negative probabilities couldn't be got low enough to make things better overall.
Would the tests that were done a few years ago for the GWML at Steventon, and which AIUI resulted in an increase in permitted wire gradient for a given speed, be of any relevance or help? Or are they only applicable to high speed lines, which this certainly isn't ?The third rail goes where it does for the former 3rd rail depot. AIUI the Westway sliproads as they are are currently either too low or would force a too steep wire gradient, although this problem is solvable - studies have looked at extending the wires to Shepherd's Bush station before, and other papers have mentioned Kensington as a future OLE changeover point.
When I last looked at extending the wires, it gave a tiny benefit to passenger trains and a reasonable benefit to freight but only if the freight could still change on the move.
Track side sensors that tell the train to drop the panto if it's still in the raised position?
It seems ridiculous that we are still reliant on trackside signs reminding the driver
The wire gradient is based on line speed and the work at Steventon decreased the gradientpeed ratio AIUI.Or are they only applicable to high speed lines, which this certainly isn't ?
Relived ?????Driver been relived and train's been inspected, pan isolated... awaiting on NR now
Well it beats being reviled, I supposeRelived ?????
That is a bit drastic isn't it ?????
Given the problem here is almost certainly the physical clearance, rather than the close spacing of two obstructions, I doubt anything at Steventon makes a difference here. I'm not sure why I mentioned wire gradient tbh.Would the tests that were done a few years ago for the GWML at Steventon, and which AIUI resulted in an increase in permitted wire gradient for a given speed, be of any relevance or help? Or are they only applicable to high speed lines, which this certainly isn't ?
A special maintenance regime and a slight reduction in speed AIUI.The wire gradient is based on line speed and the work at Steventon decreased the gradientpeed ratio AIUI.
Surely RAIB should take an interest.
( I think crews should be helped to avoid this by engineered means, it helps them in their jobs)
and removes a hazard.
If an order would be made to anybody, it would be to London Overground and the order would be to come to a stand to change traction, as GTR do at this location. No need for an infrastructure solution.Surely RAIB should take an interest. There is a pattern for some reason for these panto strikes due to crew error ( I think crews should be helped to avoid this by engineered means, it helps them in their jobs) and removes a hazard. which lead to massive disruption and in some cases passengers detaining which is life threatening. An order to Network rail is needed irrespective of cost to sort this out. Just accepting it as a fact of life is not satisfactory. West Coast has to fit CDL, Why not network rail required to fit a solution.
Surely RAIB should take an interest.
An order to Network rail is needed irrespective of cost to sort this out.
It seems ridiculous that we are still reliant on trackside signs reminding the driver being the main way this is done...