GWML Electification

[The Stationmaster]

The same way they do at Stratford when changing from GA services.

 

Yes, it will no doubt cause protests from regular commuters, particularly when services are running late - but the GWML is hardly a unique example. With Oyster now being valid to Gatwick Airport, Hertford East and Grays its not as if the extension to Reading is going to introduce problems that haven't manifested themselves before.

 

This website may be helpful when discussing Oyster on NR http://www.oyster-rail.org.uk/mixing-travelcard-and-payg/

 

But that link takes us absolutely nowhere as it says 'you only pay for the Zones not covered by your travelcard'.  So if you tap in at, say, Twyford when you hold a GWR season ticket to Paddington plus Zones 1&2  Twyford will not be covered even though you hold a valid ticket.

 

If the system could read the ticket as 'no debit due'  (as it can my Oystercard) then it would work but otherwise it would raise a charge for the journey between Twyford and, presumably, the start of the Zone where it is valid.  The important difference from the way Oyster works elsewhere is that many of the GWML are not only beyond present Oyster boundaries (which could be moved of course) and it will be in area where people will not necessarily be using it for part of their journey as they would normally have no need to.  The only way it could be accommodated is for the card readers to also recognise NR ticket data and the implication is that currently they don't.

 

Anyway back to the subject of thread and going on from the recent report from RJS.  There is definitely catenary through Tilehurst station on the MainlInes and one the next section to the east although it is difficult to see from the road if it actually extends yet to the previously quoted Scours Lane mileage - however it would at worst be only one section short of that.

 

However some of it would seem to have been put up in rather a hurry with misadjusted register arms and missing tensioning units - the catenary simply being tied off onto gantry structures in the latter case - and in places it looks to be not fully tensioned.  However as the notice below suggests it is live, and that no doubt includes the missing catenary on the Relief LInes as well    As usual click on the pictures to enlarge them. 

 

The warning sign (one of 8 on Tilehurst footbridge)

 

 

Oh no there aren't - the Down Relief directly beneath that particular sign

 

 

A different pattern of register arm - possibly something to do with locations  where greater stagger of the catenary is needed?

 

 

The more usual type of register arm - note on the further catenary (on the Up Main) the lack of tension because it is terminated on the gantry and not a tensioning unit (see detail picture further down the page).

 

 

The view westwards with the more or less complete catenary (but apparently not yet tensioned?) on the Main Lines although note the earth wire (?) still not properly fixed to the masts.  Overall however the addition of the catenary adds little extra complication to the view due to its very neat appearance

 

 

Clearly very much a matter of 'work in hand' - and a fairly clean sign that the catenary is not live and definitely not suitable for the passage of a raised pantograph

 

 

Definitely short of a tensioning unit - look closely at the way the catenary is fixed to the gantry

 

[The Stationmaster]

A problem with the alphabet soup. 'St Simon' refered to Great Western 'ATP'. If I can assume that Wiki is right ATP is a child of the 1990s BR not the Great Western in any of its incarnations.

 

Actually I thought that ATP was obsolete and TPWS was the current EU flavour. Clearly I was wrong.

 

Regards

 

Great Western ATP is one of the two trial systems of ATP installed by BR and it is very much in everyday use as St Simon said.

 

For non-believers here is a link to an industry management group which definitely uses the term -

 

http://www.rssb.co.uk/groups-and-committees/rssb-board/technical-strategy/technical-strategy-leadership-group/system-interface-committees/vehicle-train-control-and-communications-system-interface-committee/great-western-automatic-train-protection-user-management-group

[HillsideDepot]

I went out this evening for an "inspection of works" and found no visible signs of progress in the Christian Malford area, other than a big fenced compound where the Down platform would have been at the halt which appears to be for some sort of sub-station/switch gear. I couldn't see any signs of piles there, or up at Friday Street where I'd seen the HOPS train on Tuesday. That's not to say they aren't there, just that they aren't visible from the road. Certainly there are none that have "failed" and are sticking up in the air as seen elsewhere.  

 

I then continued to Grittenham (just east of Wootton Bassett Incline 'box) and again there were no sign of piling work. However driving a bit further along the lane a distant view of the line towards Vastern (Wootton Bassett direction) reveals a few masts! Not easy to see, and certainly not worth trying to photograph, but they are there. A quick trip into Royal Wootton Bassett proved no masts on the South Wales Main Line east of Callow Hill. Back on the A3102 the view is poor across to the line, but there don't appear to be masts between the ones spotted from Grittenham and Bassett Junction itself.
 

I decided to return home via Lyneham Banks, which was fortunate, as a glance across to Dauntsey Bank let me spot a few masts there. Doubling back I headed for Trow Lane which I thought was closed for parapet raising, but is actually open, even though the work is only part complete.

 

So, for what are possibly the most westerly masts (excepting Filton Depot)...

 

The view east through the bridge works fence (not the best shot, I know)

 

The view down Dauntsey Bank, with the now traditional 2 here, 3 there, random mast arrangement.

 

The Down Line pair

 

The Up Line trio

 

Trow Lane Bridge. 
 

I must admit I hadn't really expected to see masts today, if I had I'd have gone out earlier when the light was better. But for the record I hope these shots are good enough.

[phil-b259]

But that link takes us absolutely nowhere as it says 'you only pay for the Zones not covered by your travelcard'.  So if you tap in at, say, Twyford when you hold a GWR season ticket to Paddington plus Zones 1&2  Twyford will not be covered even though you hold a valid ticket.

 

If the system could read the ticket as 'no debit due'  (as it can my Oystercard) then it would work but otherwise it would raise a charge for the journey between Twyford and, presumably, the start of the Zone where it is valid.  The important difference from the way Oyster works elsewhere is that many of the GWML are not only beyond present Oyster boundaries (which could be moved of course) and it will be in area where people will not necessarily be using it for part of their journey as they would normally have no need to.  The only way it could be accommodated is for the card readers to also recognise NR ticket data and the implication is that currently they don't.

 

I still don't see what makes the GWML so special - I highlighted earlier on that Oyster is now accepted at Merstham, Redhill, Earlswood, Salfords & Gatwick Airport yet I would be willing to bet that Oyster use for locals going between these stations is absolutely minimal, particularly as there are quite a few Southern / Thameslink paper ticket deals that work out cheaper. Furthermore I expect a good proportion of travellers to London still make use of paper season tickets rather than bother with Oyster.

 

Similarly I would expect that the majority of local journeys in the outer Thames Valley served by Crossrail will still be done with paper tickets or paper season tickets even after Oyster extended there as its what people are used to and its not as though you can use Oyster on the local buses in Slough or Maidenhead like you can within the GLA area.

 

Oyster boundaries will in any case not be 'moved' - as is the case with Gatwick Airport and Hertford East services extra zones will be created which will keep fares at current levels (thus meeting the DfT requirements regarding Oyster acceptance outside the GLA area). Traffic from Reading is easily differentiated thanks to Crossrail arriving at its own dedicated station at Paddington (just as the Gatwick Express Oyster fare is triggered by the use of certain ticket gates at Victoria.

 

At the end of the day Oyster is only going as far as Reading because TfL insist it is accepted on all the services they run. There is no obligation for FGW or anyone else to allow Oyster to be used on their services.

[The Stationmaster]

I still don't see what makes the GWML so special - I highlighted earlier on that Oyster is now accepted at Merstham, Redhill, Earlswood, Salfords & Gatwick Airport yet I would be willing to bet that Oyster use for locals going between these stations is absolutely minimal, particularly as there are quite a few Southern / Thameslink paper ticket deals that work out cheaper. Furthermore I expect a good proportion of travellers to London still make use of paper season tickets rather than bother with Oyster.

 

Similarly I would expect that the majority of local journeys in the outer Thames Valley served by Crossrail will still be done with paper tickets or paper season tickets even after Oyster extended there as its what people are used to and its not as though you can use Oyster on the local buses in Slough or Maidenhead like you can within the GLA area.

 

Oyster boundaries will in any case not be 'moved' - as is the case with Gatwick Airport and Hertford East services extra zones will be created which will keep fares at current levels (thus meeting the DfT requirements regarding Oyster acceptance outside the GLA area). Traffic from Reading is easily differentiated thanks to Crossrail arriving at its own dedicated station at Paddington (just as the Gatwick Express Oyster fare is triggered by the use of certain ticket gates at Victoria.

 

At the end of the day Oyster is only going as far as Reading because TfL insist it is accepted on all the services they run. There is no obligation for FGW or anyone else to allow Oyster to be used on their services.

 

Sorry if I didn't make it clear.  A passenger at Twyford (the most likely joining point) has a GWR season ticket to London plus Zones 1 & 2 and changes to LUL at Paddington - he uses his ticket in the barrier at Paddington UndergroundD station and wherever he gets off in, say, Zone 1.  He has therefore made a valid use of the Oyster/LUL portion of his season ticket.  But on Tuesday he is delayed finding a parking space and misses his train so he catches the next one however it takes him to Paddington Crossrail Platforms 1 so he might decide to go to Bond Street or Tottenham Court Road direct as he usually goes to Oxford Street from Paddington - he has a valid ticket as his season covers him from Twyford to Paddington and Bond Street is in Zone one - so he uses his ticket in the barrier at whichever station he alights at.

 

However if we read what TfL say he has not touched in his ticket so he will be charged a maximum fare - despite having a valid ticket for the journey he has made.  Equally someone travelling from Reading to, say Peterborough will have a  valid ticket as it will include Zone 1 to enable him to get from Paddington to Kings Cross but what happens if he gets on a Crossrail train (unlikely) but it might happen if there are major delays on GWR services - he will put his ticket through the barrier at Reading but he will be exiting at an LUL station barrier without having entered via one because (if what I am told is correct) the two barrier systems cannot 'talk' to each other.

 

If you think that passengers are going to accept a situation where they do one thing before joining a train in one colour and something else before joining one in a different colour on a simple commuting trip you've yet to come across Thames Valley commuters.

 

Incidentally there will of course be a requirement on Crossrail to accept tickets other than those issued by TfL so presumably they will either have to have staff on duty, or suitable barriers to read NR tickets (which LUL already has) or leave barriers open but if they do use barriers they will have to be able to read national network codes and not just LUL codes although presumably they will have thought of that.

Edited June 2, 2016 by The Stationmaster

[phil-b259]

 

If you think that passengers are going to accept a situation where they do one thing before joining a train in one colour and something else before joining one in a different colour on a simple commuting trip you've yet to come across Thames Valley commuters.

 

But as you yourself have said in the same post they don't have too.

 

Crossrail operated stations on the GWML and GEML have a legal requirement to continue to support the full range of national rail tickets both in terms of barriers and in terms of sales. As much as TfL might not like it*, that was the stipulation made when they started taking over National Rail operations (which they subsequently branded the London Overground) and its not something they can wiggle out of now with Crossrail, however much they push Oyster. Thus our potential commuter from Twyford can still buy and use his traditional paper season ticket on Crossrail or GWR + tube.

 

However if Oyster is supported by both Crossrail and GWR then our commuter may decide to give up buying a paper season and use Oyster regardless of the train they get. If GWR conversely want nothing to do with Oyster then our commuter is best advised to stick to a paper season ticket to preserve their flexibility.

 

Yes if a commuter purchases both a paper season and uses an Oyster card, on some days they will effectively end up paying twice - but this is no different to a Southern commuter from Redhill using his Oyster card despite having a paper season and also paying twice for a single journey.

 

* Note how London Overground gets included in all TfL maps but other rail services (including Thameslink across central London) get ignored in a 'not part of our empire so we will ignore them' mode.

Edited June 2, 2016 by phil-b259

[Titan]

 

A different pattern of register arm - possibly something to do with locations  where greater stagger of the catenary is needed?

 

 

This is the arrangement for 'low encumbrance' That is for when a small distance between catenary and contact wire is required, for example on approaching a low bridge in order to minimise the overall height of the system - it is no coincidence that there is a footbridge in the background.  The two brackets hanging down vertically can be swung in the along track direction to any angle required up to and including horizontal to cater for very low system heights down to 280mm. In this case the catenary would actually go between the registration arm and the registration tube to which the arm is attached.

[phil-b259]

A problem with the alphabet soup. 'St Simon' refered to Great Western 'ATP'. If I can assume that Wiki is right ATP is a child of the 1990s BR not the Great Western in any of its incarnations.

 

Actually I thought that ATP was obsolete and TPWS was the current EU flavour. Clearly I was wrong.

 

Regards

 

BR ATP as fitted to the GWML is a expensive but far superior system to TPWS, but requires significant expense to provide in terms of train and track equipment. It is also, in technology terms, very outdated and due to its limited application quite a costly system to maintain. TPWS by contrast was a well intentioned, but fundamentally a knee jerk response to the Ladbroke Grove crash. While TPWS was quick to roll out across the country and has been very effective in preventing similar head on crashes at a modest cost, because it is not fitted to every signal it does not provide the comprehensive train protection ATP does. As such the BR ATP  has to remain in service until it can be replaced with the new EU sponsored ETCS system which will maintain the same level of protection on the GWML

 

You should also note that Heathrow Express and Heathrow Connect EMUs do not have AWS / TPWS fitted as a result - ATP provides more than adequate protection.

 

However due to delays in developing the ETCS system there is some doubt it can be up and running on the GWML before Crossrail starts operations. As Crossrail trains will not have ATP fitted an interim solution has been proposed which involves fitting TPWS to every signal on the GWML. This has bee opposed by GWR, HEX and the unions as a retrograde step as even TPWS at every signal does not provide the same level of protection as ATP, but faced with the alternative of delaying the start of Crossrail services the ORR has accepted the proposals

Edited June 3, 2016 by phil-b259

[St. Simon]

However due to delays in developing the ETCS system there is some doubt it can be up and running on the GWML before Crossrail starts operations. As Crossrail trains will not have ATP fitted an interim solution has been proposed which involves fitting TPWS to every signal on the GWML. This has bee opposed by GWR, HEX and the unions as a retrograde step as even TPWS at every signal does not provide the same level of protection as ATP, but faced with the alternative of delaying the start of Crossrail services the ORR has accepted the proposals

 

ETCS Level 1 will be operational at Christmas this year on the Heathrow Branch, the ETCS Level 2 overlay between Paddington and Stockley will be integrated by Christmas 2017

 

Additional TPWS loops has not only been proposed, but approved. The remit isn't to fit ALL signals with TPWS loops, it is to fit signals with a significant risk of a rear end collision resulting from a SPAD between Paddington and Stockley, where this has been identified through risk assessments involving all TOC's and FOC's on the route as not requiring additional protection, this has not been provided. Also, the remit includes the requirement to stop 9%G braked passenger trains within the overlap rather than before the conflict, where the overlap is shorter, unless a risk assessment has agreed that this isn't possible or necessary. 

 

From the meetings and conversations I have had with operations and drivers, there has been no opposition as far as I can see with the scheme. Additional TPWS is not being fitted to replace ATP, ATP equipment is still being fitted to all new signals that require it being installed as part of Crossrail, it is being provided to provide protection to Crossrail trains, whilst giving additional protection on top of what's there to GWR, HEx, HC and DBC trains  

 

Simon

Edited June 3, 2016 by St. Simon

[Edwin_m]

BR ATP as fitted to the GWML is a expensive but far superior system to TPWS, but requires significant expense to provide in terms of train and track equipment. It is also, in technology terms, very outdated and due to its limited application quite a costly system to maintain. TPWS by contrast was a well intentioned, but fundamentally a knee jerk response to the Ladbroke Grove crash. While TPWS was quick to roll out across the country and has been very effective in preventing similar head on crashes at a modest cost, because it is not fitted to every signal it does not provide the comprehensive train protection ATP does. As such the BR ATP  has to remain in service until it can be replaced with the new EU sponsored ETCS system which will maintain the same level of protection on the GWML

 

You should also note that Heathrow Express and Heathrow Connect EMUs do not have AWS / TPWS fitted as a result - ATP provides more than adequate protection.

 

However due to delays in developing the ETCS system there is some doubt it can be up and running on the GWML before Crossrail starts operations. As Crossrail trains will not have ATP fitted an interim solution has been proposed which involves fitting TPWS to every signal on the GWML. This has bee opposed by GWR, HEX and the unions as a retrograde step as even TPWS at every signal does not provide the same level of protection as ATP, but faced with the alternative of delaying the start of Crossrail services the ORR has accepted the proposals

A very slow knee jerk if so, as I was working on developing it in about 1994 (as was another member on here) but it was up to the turn of the century before it was installed. 

 

It was predicted to avoid about 70% of the casualties of a full ATP system at far less cost and quicker fitment, and despite this being criticised by Uff-Cullen it was borne out in service.  It also arguably avoided sending our railway down the much more expensive technological dead-end of fitting GW-type ATP to the whole network only to have to replace it by ERTMS only a few years later.

 

Fitting TPWS at every signal ought to be pretty effective for stopping multiple unit passenger trains when committing SPADs.  Possibly not for stopping freight trains before any collision, but the freights aren't fitted with ATP anyway so this won't be a deterioration in safety.  It will also increase protection for the suburban stock which was never ATP fitted either. 

Edited June 3, 2016 by Edwin_m

[phil-b259]

A very slow knee jerk if so, as I was working on developing it in about 1994 (as was another member on here) but it was up to the turn of the century before it was installed. 

 

 

I meant knee jerk as in following the Ladbroke Grove accident there was a rush to get TPWS in as quickly as possible. Given you say the system was in development back in 1994, and the fact the need for such a system was well known as far back as 1991 but it took the deaths of 31 people in 1999 to focus minds into actually getting TPWS rolled out as quickly as possible, the use of the term 'knee jerk reaction' to describe said roll out is not totally inaccurate.

[phil-b259]

 

 

From the meetings and conversations I have had with operations and drivers, there has been no opposition as far as I can see with the scheme. Additional TPWS is not being fitted to replace ATP, ATP equipment is still being fitted to all new signals that require it being installed as part of Crossrail, it is being provided to provide protection to Crossrail trains, whilst giving additional protection on top of what's there to GWR, HEx, HC and DBC trains  

 

Simon

 

There was an official ORR consultation about the proposals and ASLEF were among several groups that made representations that they considered NRs proposals unacceptable.

 

http://orr.gov.uk/__data/assets/pdf_file/0006/19392/crossrail-exemption-application-consultation-aslef.pdf

 

http://orr.gov.uk/consultations/closed-consultations/railway-safety-consultations/crossrail-exemption-application-consultation

 

Individual drivers may of course feel differently but if so they are not reflecting their unions stated position.

[Edwin_m]

I meant knee jerk as in following the Ladbroke Grove accident there was a rush to get TPWS in as quickly as possible. Given you say the system was in development back in 1994, and the fact the need for such a system was well known as far back as 1991 but it took the deaths of 31 people in 1999 to focus minds into actually getting TPWS rolled out as quickly as possible, the use of the term 'knee jerk reaction' to describe said roll out is not totally inaccurate.

As far as I recall it was on John Prescott's desk at the time of Ladbroke Grove, awaiting sign-off of the funding.  So maybe a knee-jerk on the part of Prescott.  And contrary to what some people (though not you) still believe, TPWS would have prevented Ladbroke Grove if fitted to SN109 and the Thames Trains unit. 

Edited June 3, 2016 by Edwin_m

[The Stationmaster]

As far as I recall it was on John Prescott's desk at the time of Ladbroke Grove, awaiting sign-off of the funding.  So maybe a knee-jerk on the part of Prescott.  And contrary to what some people (though not you) still believe, TPWS would have prevented Ladbroke Grove if fitted to SN109 and the Thames Trains unit. 

 

In view of the distance the turbo travelled after SPADing SN109 I can't see how anyone would doubt that TPWS would have stopped it.  However the Up train also needed to be stopped although it would probably have stood a much better chance if the turbo had been stationary.

 

Mind you if the Driver had known the road properly the turbo would also have stopped - although probably not as soon as TPWS would have halted it.

[Northroader]

As its half term, I was able to get a window seat both ways this morning going up to the smoke, and better able to indulge in the sport of mast spotting. There are a few masts up at Uffington, then on the stretch Challow to around half mile west of Steventon, over half are up on the down side, and a lower proportion on the up side. There's a gap through Steventon, then from level with Milton into Didcot all the masts and fittings are waiting for wiring. This is the same to east of Moreton cutting, then wiring starts. The down main is wired form there to level with the Loveerock road estate in Reading, apart from a short length of contact wire missing through Goring. The up main is wired from around south Stoke as far as Loveerock estate, apart from a gap from north of Pangbourne to north of Basildon bridge. The relief lines wiring begins from north of Cholsey, but have more gaps, contact wire or both, the down relief Cholsey to south Stoke, up relief through Pangbourne. The relief lines wires stop at the Roebuck. Scribbling on an HST I might have missed some, and some bits looked like the quick lash ups described by Mike stationmaster yesterday. Still, it's nice to see the main lines shaping up.

East of Reading there's a big void in mast erection to just short of Maidenhead, some at Twyford west on the upside, and east end of Sonning cutting on the downside.

[Banger Blue]

The 'dive under' to/from the Southern can be accessed via Platforms 13/14/15 as can be seen in this screenshot:

 

[Edwin_m]

In view of the distance the turbo travelled after SPADing SN109 I can't see how anyone would doubt that TPWS would have stopped it.  However the Up train also needed to be stopped although it would probably have stood a much better chance if the turbo had been stationary.

 

Mind you if the Driver had known the road properly the turbo would also have stopped - although probably not as soon as TPWS would have halted it.

The point was set for the Up HST so if the Turbo had been stopped before the fouling point, the HST would have continued along its planned route, possibly being stopped by a signal going to red in its face but with no collision.  With the length of overrun from SN109 to the fouling point, TWPS would certainly have stopped the Turbo. 

[phil-b259]

In view of the distance the turbo travelled after SPADing SN109 I can't see how anyone would doubt that TPWS would have stopped it.  However the Up train also needed to be stopped although it would probably have stood a much better chance if the turbo had been stationary.

 

Mind you if the Driver had known the road properly the turbo would also have stopped - although probably not as soon as TPWS would have halted it.

 

How fast was the Turbo going and what was the overlap available past SN109 - because if TPWS had been installed in accordance with current standards (which haven't changed since the rollout of TPWS commenced) the Turbo would definitely have been stopped before it had a chance to get in the way of the HST.

 

Note:- for non railway persons, TPWS standards dictate that if a passenger train is going at less than 75mph and the weather / rail head conditions are normal, that train will be bought to a halt within the standard 200yard overlap (and thus before it gets the chance to run through any points and end up foul of another line).

 

The exception to this is if a less than standard overlap is provided, the railhead conditions / weather is particularly bad or the train is going faster than 75mph. In the last of these scenarios, if the consequences of a train not coming to a halt within the overlap are thought to be significant the installation of TPWS+ will cater for speeds grater than 75mph.

[RJS1977]

In view of the distance the turbo travelled after SPADing SN109 I can't see how anyone would doubt that TPWS would have stopped it.  However the Up train also needed to be stopped although it would probably have stood a much better chance if the turbo had been stationary.

 

Mind you if the Driver had known the road properly the turbo would also have stopped - although probably not as soon as TPWS would have halted it.

 

Can TPWS be over-ridden in a moving train in the same way AWS can? If the driver of the Turbo at Ladbroke Grove over-rode his AWS, who's to say he wouldn't have over-ridden TPWS as well?

[The Stationmaster]

How fast was the Turbo going and what was the overlap available past SN109 - because if TPWS had been installed in accordance with current standards (which haven't changed since the rollout of TPWS commenced) the Turbo would definitely have been stopped before it had a chance to get in the way of the HST.

 

Note:- for non railway persons, TPWS standards dictate that if a passenger train is going at less than 75mph and the weather / rail head conditions are normal, that train will be bought to a halt within the standard 200yard overlap (and thus before it gets the chance to run through any points and end up foul of another line).

 

The exception to this is if a less than standard overlap is provided, the railhead conditions / weather is particularly bad or the train is going faster than 75mph. In the last of these scenarios, if the consequences of a train not coming to a halt within the overlap are thought to be significant the installation of TPWS+ will cater for speeds grater than 75mph.

 

The turbo was travelling at 40mph according to the Cullen Report.  i can't find a reference anywhere to the overlap distance but it would almost certainly have been a standard overlap as there was not much reason for it to be otherwise however it might possibly have been swung according to the route set in advance of SN109 depending on how close the signal was to the facing points in advance of it.

 

What I do know is that there was a massive overrun margin, c.800yds+ in advance of the last place at which the train could have turned onto a correct route  (it could either have gone left at the first point it reached - which is probably where it would have been booked to go, onto the Down Main, or to the right at the next point some way beyond that - although that would have taken it back to the line it had left to arrive at SN109).

[phil-b259]

Can TPWS be over-ridden in a moving train in the same way AWS can? If the driver of the Turbo at Ladbroke Grove over-rode his AWS, who's to say he wouldn't have over-ridden TPWS as well?

 

Basically no.

 

TPWS has a 'overide' button (that must be pressed when stationary for it to work) which disables the TPWS for 20 seconds so as to allow for drivers being cautioned past red signals in failure conditions but basically once a train has been 'tripped' by the TPWS the driver has no choice but to let it bring the train to a halt.

 

Obviously there are isolation devices that can be used to turn TPWS off if there is a loco / unit has a fault with it but (1) they are not usually accessible from the driving position, (2) It is strictly forbidden for a train to remain in service if the TPWS (or AWS) is defective and (3) You cannot hide its operation / isolation from the data loggers which is why one ex Thameslink driver has served a prison sentence for disabling it without authorisation and is why the driver of Tangmere is being taken to court over the Wootton Basset incident.

[DY444]

But that link takes us absolutely nowhere as it says 'you only pay for the Zones not covered by your travelcard'.  So if you tap in at, say, Twyford when you hold a GWR season ticket to Paddington plus Zones 1&2  Twyford will not be covered even though you hold a valid ticket.

 

If the system could read the ticket as 'no debit due'  (as it can my Oystercard) then it would work but otherwise it would raise a charge for the journey between Twyford and, presumably, the start of the Zone where it is valid.  The important difference from the way Oyster works elsewhere is that many of the GWML are not only beyond present Oyster boundaries (which could be moved of course) and it will be in area where people will not necessarily be using it for part of their journey as they would normally have no need to.  The only way it could be accommodated is for the card readers to also recognise NR ticket data and the implication is that currently they don't.

 

 

I think you're getting confused between different things.  As and when Oyster is accepted at Twyford then:

 

a.  If you travel between Twyford and Central London and the only ticket you posses is a Zone 1/2 Oyster travel card then you must tap in at Twyford and have sufficient PAYG credit on the Oyster card.  In this case the fare from Twyford to the Zone 1/2 boundary will be deducted when you tap out at the end of your journey.  In theory different fares could be charged if you tap out at Paddington GWR Mainline station rather than at a TFL station or Paddington Crossrail.  Travelling the other way then you must tap out at Twyford.

 

b.  If you hold an Oyster season ticket from Twyford to Zone 1/2 then you are not obliged to tap in or out providing you stay within the zones/area covered by the season ticket.  Oyster season ticket holders only have to tap in/out to open ticket barriers or if they travel to/from a station outside the zones/area covered by the season ticket (as in a above).

 

c.  If you hold a paper ticket from Twyford to Zones 1/2 then the issue doesn't arise

Edited June 4, 2016 by DY444

[Peter Kazmierczak]

Just back from West London.

 

Will post some pictures of the line between Hayes & H and Iver  if anyone's interested.....

[96701]

Just back from West London.

 

Will post some pictures of the line between Hayes & H and Iver  if anyone's interested.....

Yes please. It would be nice to return to the topic instead of all this rattling about TPWS and ticketing.

[Peter Kazmierczak]

Rightio!

 

Dull morning today, but at Airport Jn track (concrete slab) has now been laid along the new Up Airport ramp.

 

Still not sure about the geometry of this bit though.....

 

This took my eye in the compound on the up side of the line. What's this all about then? New mini-layout by Stubby?

Edited June 4, 2016 by Peter Kazmierczak