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Posts posted by Edwin_m

  1. 1 hour ago, Rivercider said:

    It is a curious mix of stock. Perhaps a cripple trip or transfer to or from a carriage and wagon depot.

    Is that a the remains of a railway over bridge just above the loco?



    Looks like it's being hauled by an 08 or similar shunter, suggesting either a short-distance move or a line that's not very busy.  

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  2. As far as I can see there are two effects of Covid on society in general and the rail network in particular.  


    Firstly many people can't travel due to restrictions, or don't wish to because whatever they would have wanted to go to is closed, or they are just afraid of catching it.  I think that effect will fade away during 2021 as vaccination becomes widespread.  The rail network nearly collapsed in 2000 after the Hatfield derailment, when there was a perceived (but turned out not actual) risk of similar accidents and the network was crippled by speed restrictions.  But passengers came back quite quickly once the situation was resolved.  


    The longer term impact is likely to be a permanent shift towards working from home instead of commuting, possibly also a reduction in business travel due to people meeting remotely instead for cost reasons (though I think many companies were already doing that after 2008).  Somewhere between the two is the likely medium-term reduction in leisure travel due to some attractions not having survived the pandemic, but which ought to be replaced eventually.  

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  3. I've seen other articles by Ian Jack, though not recently, and he does seem quite knowledgeable about aspects of our industrial history particularly around Glasgow.  


    Good point about "commuters" - it literally means those who have their fair "commuted" by buying a season ticket, so by that test some of the three-day-a-weekers probably don't qualify either.  I would regard it as describing those that travel to and from a workplace, not those travelling for other purposes such business meetings elsewhere. 


    My own view is that we'll see a bigger drop in peak demand than off-peak as many office workers work from home at least part of the time, and some may just come in for meetings during the day which might even add to the off-peak demand.  In the long term that might result in a more healthy railway as the peaks will be reduced relative to the off-peaks, but some of the trains and infrastructure that are only needed a couple of times each day might end up redundant.  

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  4. 1 hour ago, sir douglas said:

    this one isnt mine, it was in a recent Tank Museum video and i was just curious where it is. the context of it int he video was just about designing and building tanks narrow enough to fit onto wagons,  this specific place or date was irrelevent and not mentioned


    it looks like a junction with main lines going behind the signal box, with the main window side of it on the other side suggesting that is the more important or earlier route. there looks to be a platform in the background.

    Capture (4).JPG

    Both switch blades are open on the first points beyond the level crossing on the unoccupied track, suggesting a trapping function which may mean the route in the foreground is a goods line and the one diverging behind the box is passenger.  

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  5. The original plan was for HS2 to take over the surface alignment of the Ruislip line, but they then decided to put it underground but the line would need to be closed to locate ventilation shafts on the formation.   At some stage the shafts were moved so the track could remain.  


    More recently there was some talk of using it to take away the spoil from digging the big hole for the station, but they now seem to have decided to build an underground conveyor to load it onto trains at the former Wembley Euroterminal instead.  

    • Informative/Useful 3
  6. I believe Chiltern are very interested in keeping the option open of terminating some of their services at OOC.  Interchange to HS2 may not be so important, as passengers doing that would be doubling back on themselves and north of a certain point would be better off heading directly for Birmingham.  But there are other connections to be made, particularly Heathrow.  It also helps get round the limited platform capacity at Marylebone.  

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  7. Phase 1 is essentially a trunk route to get people between London and the Midlands or beyond, so doesn't directly benefit the areas it passes through.  The indirect benefit of allowing better service on the existing routes is hard to sell, especially to people who don't use the train at all.  Nearly every local authority in the North is in favour of Phase 2 and popular opposition seems to be localised in a few areas where it is most disruptive.  

    • Like 2
  8. This RAIB Safety Digest covers an accident where the electric locking was partly responsible.  The points were worked electrically from levers, and detection was displayed on an indicator and checked in the electric locking for the signal to clear.  Lack of detection didn't physically lock any levers, unlike a mechanical setup where the facing point lock lever wouldn't go fully over unless the point was correctly set. 


    The signaller, somewhat flustered, failed to check the detector lights behind the levers and concluded from the positions of the levers that everything was correctly set but that there was some fault with the signal.  When they instructed the train to proceed it was derailed on a point that had not gone fully over.  

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  9. 4 minutes ago, DY444 said:


    Slightly strange story given the batch of ETCS equipped 387s which started on Heathrow Express recently. 

    It does seem odd that a "first in class" 387 is considered necessary when a fleet fitment already exists, and that it is implied that the same design is replicable on all the other Electrostar classes.  Most of the earlier ones have quite significant differences from the 387, not least having been built before future provision for ETCS became mandatory.  I can only think the "first in class" is related to the issues that might arise during DC operation, or that they've got the class number wrong and they should be referring to a 375.  

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  10. 5 hours ago, Miserable said:

    But the fact it it was (is?).

    I can't speak for "was", but unlikely it still "is" I think.  Otherwise, as every train is continuously braked these days, there would be no need for Absolute Block signallers to observe tail lights in these situations.    The tail light cameras I mentioned show this isn't the case.  

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  11. It's possible the train divided just round the corner and the front portion continued into the loop as normal leaving the rear portion somewhere behind.  I believe the incident mentioned by Stationmaster was one where the compressor in the loco was powerful enough to make good the loss of air from the pipe, so the front portion continued as normal.  


    As far as I'm aware signalmen weren't and aren't allowed to assume a train is complete unless they've actually seen the tail lamp or had some confirmation that it is present.  So I'm not sure why the continuous brake should be relied on to prove completeness in this case but in no other.  


    These days tail lamp cameras are often used if there is a need to confirm the train complete before the rear has passed the box.  

    • Like 1
  12. On 25/11/2020 at 15:24, Miserable said:

    I was a guard and then signalman, so I'm pretty au fait with the regs c. 1980. FWIW the guard was required to ring the signalman when the train had arrived in a loop (where the bobby couldn't see the tail lamp themselves) and report 'Train arrived complete with tail lamp' before the bobby could give 2-1 ('Train out of section') . If I had £1 for every Guard who then walked back a actually checked the lamp was there (which was entirely unnecessary) I'd be rich - there was no hand or lamp signal for doing such.

    I guess if the tail lamp had been missing or unlit the train would have been pulled up on its way out of the loop or stopped at the next box.  So perhaps just as well to check on arrival.  

  13. There appears to be a main signal facing the camera just where the train is joining the main line on the OP, which doesn't appear on the RCTS photo.  On the original, is this in fact a signal and is it "off"?  If so then it's pretty definite that the train is heading away from camera.  

  14. 1 hour ago, Nick C said:

    Definitely one of those situations where the factors all added up - the point motorizing being 'done on the cheap' with the levers not repainted and the locking not adjusted, then the signalman being unfamiliar with the system and being fatigued, and then the actual failure itself of the batteries.

    Going by the picture in the report, the levers looked freshly painted - just not in the correct colour scheme!  

  15. On 19/12/2020 at 11:15, phil-b259 said:

    On a signalling panel setup additional circuitry is provided to have 3 lights above / below the switch showing Normal, Out Of Correspondence (i.e. we have no idea what the points are doing) and Reverse. I presume IECC setups have something similar.

    Just to complete this angle, Out of Correspondence is indicated when the points are not detected in either position, or when the position the are detected is different from that which they have been controlled to (either by setting a route or by operating the point switch).  IECCs show this by flashing the screen character representing that set of points - I think (some?) panels flash the appropriate lights on the track diagram.  


    One thought that occurs with indicators is that they are aligned with but some distance behind the lever they relate to, especially when the lever is reversed.  If the signaller was to one side when operating the lever there might be a risk of mis-reading the indicator for an adjacent lever.  


  16. 22 hours ago, Michael Hodgson said:

    You often cant see very far along the line from a car anyway, and road traffic may often be 50 mph or more. 

    If you slow down too much you'll cause a collision with other road users.

    There's also the risk if slowing or stopping that a driver will get into the wrong gear and stall on the crossing itself.  

    21 hours ago, Jim Martin said:

    I take it that the idea of the predictors is to tailor the amount of time the barriers are down to the speed of the train; so you don't get the situation where the barriers close then nothing happens for ages because the approaching train's going well below line speed?

    That's the intention but the system alters the start of the crossing sequence, not the time the barriers are down, so as to keep the barrier-down time moreorless constant.  

  17. 1 hour ago, Northmoor said:

    This makes sense since the trains are going to be going rather faster than through any of the other tunnels; the air's got to go somewhere.

    Comparing the HS2 diameter with that of the Channel Tunnel, which carries much taller road vehicle shuttles, confirms that the aerodynamics are more important than the train size.  

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  18. 9 hours ago, Joseph_Pestell said:

    I don't know what the political situation in the US is with regard to this. They would certainly be "able" to do this in California but they may not be willing to make the financial investment. I understand that, despite it being the wealthiest state in the Union, California is a bit of a basket-case where public finances are concerned.

    The cost of renewables has fallen sufficiently that private investment has shifted towards them and coal production and use has reduced even while Trump has been trying trying to encourage it. 


    That isn't really the case with batteries or other energy storage yet, which are likely to be need alongside renewables, but the move to electric cars presents opportunities.  For example their owners might be happy to be paid for the car battery to be used as a buffer against supply fluctuations while it's charging overnight, as long as they are left with enough charge to cover the next day.   And electric car batteries that are older and losing efficiency might still be good enough to be re-used in static "battery farms".

    • Informative/Useful 1
  19. 6 hours ago, corneliuslundie said:

    And nuclear? Which century shall we see another nuclear power station on line in the UK?

    There's one under construction at Hinckley Point.  I imagine they expect to finish it in less than 80 years.  

    6 hours ago, corneliuslundie said:

    Then we switched to diesel as the motive power for the railways. In primary energy terms this is more efficient than electricity from oil fired power stations, mainly because of the distribution losses. So there was not really an argument for electric railways in primary energy terms.


    And now that we are not using fossil fuels so much for generation the whole calculation changes again. I am not trying to make a point for or against any of these approaches, merely that it is not at all simple.

    When diesel was the preferred power source for trains, the preferred power source for electricity was still domestically-mined coal.  An electric railway was a more efficient way of using coal than a steam railway.  Today there is a wide range of possible power sources and we don't really know which ones will dominate in the future.  But all of them will probably work best when producing electricity, so an electric railway can use any of them.  


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  20. 5 hours ago, Nearholmer said:

    It is a conundrum, isn't it?


    One option, although I'm not sure how thermally efficient it could be made*, surely has to be to swap out gas boilers for electric boilers, and retain water as the medium for final transport of energy in "legacy houses". But, even that poses questions about the capacity of street mains and domestic connections if no energy store is provided at the house, given that gas boilers typically have ratings higher than the rating of the typical domestic electrical connection.


    Add this one to questions about capacity and points of connection for electric vehicle charging and it gets even more interesting, and to me it does tend to point in the direction of domestic energy storage, to remove large peaks from demand, whether that be by storing energy in batteries (including, of course, using the car battery to support domestic demand), or in warm bricks (storage heater technology), or by some other means.


    Insulate your house and buy thermal undies!


    *The answer to that seems to be "compared with what?". An electric boiler will be more thermally efficient than even the best gas boiler, because there are no losses via a flue. But, how an electrically heated water-medium system compares in efficiency with direct electric heaters I'm still not sure - it must be lower efficiency, but my gut feel is not hugely.


    2 hours ago, Grovenor said:

    From what I've seen the conversion from gas is supposed to be to heat pumps, either air source or ground source.

    Apparently an air source heat pump can be used to run radiators, but can only heat water to around 45 degrees.  This possibly makes it more thermally efficient than a gas boiler, because the lesser temperature difference between the pipes and their surroundings means less heat is lost in places it isn't needed.  But it also means most radiators will need replacing with larger ones.  


    A heat pump is arguably more than 100% efficient, because the amount of useful heat out is (hopefully) more than the amount of electrical energy needed to power it.  

    • Thanks 1
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  21. 50 minutes ago, Mike Storey said:

    Of course, if electric cars and trucks become a reality within the HS2 timeframe, then the argument revolves around the environmental costs of producing those vehicles, not purely running them. 

    Electric vehicles will still produce tyre particulates, which appear to be a significant fraction of total pollution.  In fact, being heavier than the equivalent IC vehicles, they may produce more.  

    • Informative/Useful 1
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