Thameslink - power changeover question

[Michael Hodgson]

I can't help wondering whether a track layout serving the old York Road Platform could have been compatible with the relatively recent Platform Zero.  The works associated with the reinstatement of the disused Gaswork Tunnel and the station remodelling would certainly have been different.  Kings Cross already has a platform 9¾,  they could have called this one number minus one!

[009 micro modeller]

18 hours ago, Michael Hodgson said:

I can't help wondering whether a track layout serving the old York Road Platform could have been compatible with the relatively recent Platform Zero.  The works associated with the reinstatement of the disused Gaswork Tunnel and the station remodelling would certainly have been different.  Kings Cross already has a platform 9¾,  they could have called this one number minus one!

Was there any kind of physical connection to St Pancras prior to the linking into Thameslink of the GN suburban lines?

[Edwin_m]

19 hours ago, Michael Hodgson said:

I can't help wondering whether a track layout serving the old York Road Platform could have been compatible with the relatively recent Platform Zero.  The works associated with the reinstatement of the disused Gaswork Tunnel and the station remodelling would certainly have been different.  Kings Cross already has a platform 9¾,  they could have called this one number minus one!

Looking at the space available, I think a connection to York Road for a decent length of train would have made it impossible to use the easternmost of the tracks through Gasworks Tunnel for anything else.  In any case, the connection for return services on the other side of the station has now disappeared underneath the newish station building extension.  These curves were always heavily restricted due to clearance, so probably couldn't have taken even the few classes that are cleared for the Thameslink core.  

[Mike Harvey]

Not directly on topic  but two highly visible changeovers take place on the Midland Metro within about 200 metres of each other. Trains run between New Street and the end of the line at Egbaston Village on battery power. There is a short energised overhead line section between Brindley place and the adjacent stop at Five Ways, presumably to provide a charging boost to the batteries if required. Trams run with the pantograph up in both directions with changeover performed whilst stationary in the platforms. The line is double tracked.

[Titan]

On 27/09/2022 at 17:50, Michael Hodgson said:

I can't help wondering whether a track layout serving the old York Road Platform could have been compatible with the relatively recent Platform Zero.  The works associated with the reinstatement of the disused Gaswork Tunnel and the station remodelling would certainly have been different.  Kings Cross already has a platform 9¾,  they could have called this one number minus one!

 

Well... If the remodeling was done to the plans I saw a few years ago, when the platforms are renumbered there will be an actual but disused platform between 9 and 10...

[Wickham Green too]

Plans drawn by someone called Rowling ??!?

[andyman7]

On 27/09/2022 at 09:52, phil-b259 said:

 

All trains routed via Elephant & Castle (thats those on the Wimbledon loop and Shortlands) can only be 8 cars due to short platform lengths.

 

If you do see a 12 cart on this route it will be a (slow) non-stop diversion away from London Bridge via Streatham Common and Herne Hill

The 'alternative' Blackfriars - East Croydon route is via Herne Hill - Tulse Hill - West Norwood - Norwood Junction - East Croydon; they don't go via Streatham Common (but they do go past my house)

[phil-b259]

8 minutes ago, andyman7 said:

The 'alternative' Blackfriars - East Croydon route is via Herne Hill - Tulse Hill - West Norwood - Norwood Junction - East Croydon; they don't go via Streatham Common (but they do go past my house)

 

They DO go via Streatham Common on occasion if engineering work or an incident (eg. suicide occurs) at Norwood Junction blocking all lines then the Streatham Common - Tulse Hill route IS used to maintain a service (subject to drivers route knowledge) with the 700s cleared for this routing.

Edited September 29, 2022 by phil-b259

[Michael Hodgson]

6 hours ago, Titan said:

 

Well... If the remodeling was done to the plans I saw a few years ago, when the platforms are renumbered there will be an actual but disused platform between 9 and 10...

The suburban station has indeed gone back to only two platforms again (for many years 11 lacked rails but had to be put in because of the steady increase in commuting).  9 is still there, 10 was lifted, and Platform 11 was renumbered to 10.

 

9 3/4 is now a shop doing a roaring trade selling all manner of Harry Potter merchandise.  It's accessed from the new concourse, the doors being in what was the outside wall of the main station.  There's half a shopping trolley fastened to the wall, and a long queue of tourists waiting to pose wearing a scarf while the shop's photographer takes a few shots for which they pay a handsome fee.    

 

There was an earlier incarnation of Platform 9 3/4 before the remodelling.  That was just a simple sign placed on the outside wall of the suburban station.  Not many people knew about it, you could see it if you used the normal route from platform 8 (main station) to get to the suburan platforms.  A Japanese couple once asked me to take their picture while they posed under this sign.

 

When the film was being made, a screen of polythene sheeting and scaffolding poles was erected for a couple of weeks around two of the platforms in the main station, but I can't now remember whether that was 3&4 or 5&6

[robertcwp]

I believe dual voltage Electrostars and other modern units can change on the move and this happens on the West London Line where the wires stop just north of the Westway, because back in the late 1960s it seems no one thought of building the bridges high enough to allow for the line under them to be wired up. When 313s were on the line, they had to stop to change over. 

 

When 319s were first introduced, there was a problem when a unit became gapped on DC. On regaining power, unless the driver pressed a particular button (possibly the DC button) the pantograph would go up. It would either reach its maximum height then fold itself down and lock so it could not be raised at Farrindgon or it would, and in some cases did, hit a signal gantry or bridge.

[Mike_Walker]

Unless there's been a change recently, only London Overground trains (378s) are allowed to change systems on the move on the West London Line.  Southern 377s have to stop and do it.  This is near North Pole and not in a station.

[stewartingram]

Not changing power on the move, but 365s on the GN electrics used to lower pantographs to run through dead sections (for engineering reasons), then raise them later on. I experienced this a few times when I was commuting - better than bustitution!

[Oldddudders]

On 29/09/2022 at 17:02, Wickham Green too said:

Plans drawn by someone called Rowling ??!?

Probably not - but she has had correspondence with the SM at KX.  Somewhere I have a photocopy of a letter in response to one from him. I know my copy is genuine, because I put the original through the SM's photocopier. 

[jim.snowdon]

12 hours ago, Mike_Walker said:

Unless there's been a change recently, only London Overground trains (378s) are allowed to change systems on the move on the West London Line.  Southern 377s have to stop and do it.  This is near North Pole and not in a station.

The idea that pantographs could be raised whilst on the move came distinctly late to Network Rail and the train operators, who seem to have been oblivious that the French, Dutch and Americans (at least) had been doing it for decades. The TGV sets were changing from 25kV AC to 1500V DC on the move, with pantograph changeover as soon as the Paris - Lyons LGV was inaugurated. So too have the Euroshuttle sets, both 750V DC 3rd rail to 25kV OLE and 25kV to 3kV DC, all without getting tangled up in the knitting.

 

The Dutch and Americans think nothing of gapping the overhead at lifting bridges, letting the pantograph rise free and then picking up the ramped contact wire on the other side of the gap. (British pantographs can't do this on account of the ADD function.)

 

[D7666]

On 27/09/2022 at 09:52, phil-b259 said:

 

All trains routed via Elephant & Castle (thats those on the Wimbledon loop and Shortlands) can only be 8 cars due to short platform lengths.

 

If you do see a 12 cart on this route it will be a (slow) non-stop diversion away from London Bridge via Streatham Common and Herne Hill

 

It is not unknown for a 700/1 to do Wimbledon loop during service disruption - although to my knowledge not recently as they are more inclined to cancel; it certainly happened in earlier 700s days.

 

700s ASDO is intelligent enough (i.e. programmed intelligently by people who actually thought about these things) that if a 12car (FLU) stops at the 8car (RLU) marker board at a nominally 8car patform, only the front 8 cars doors are released.

 

Indeed, if a 12car stops at a nominally 7car platform (e.g. Hendon) only the front 5 are released, and so on. Automatically. They were doing this last week - on the Tue. and Wed. industrial action days, there was a mix of FLU and RLU doing the special Bedford STPancras services - and it worked that at STP an Up semi formed a Down stopper and v.v. and the unit workings were muddled between both types - I did 12car 700s stopping at Hendon and Kentish Town both ways, one Up one day one Down the other. In all cases ASDO worked exactly right.

 

Edited December 24, 2022 by D7666

[The Stationmaster]

On 07/10/2022 at 11:22, Mike_Walker said:

Unless there's been a change recently, only London Overground trains (378s) are allowed to change systems on the move on the West London Line.  Southern 377s have to stop and do it.  This is near North Pole and not in a station.

The static changeover process was readily viewed from the Eurostar North Pole depot control room.  Well worth visiting if you wanted a good laugh looking at some sort of prehistoric idea of operating a dual voltage electric train while your own could happily changeover from 3rd rail to 25kv overhead, or vice versa while travelling  at 100mph.

[roythebus1]

On 06/10/2022 at 21:12, robertcwp said:

I believe dual voltage Electrostars and other modern units can change on the move and this happens on the West London Line where the wires stop just north of the Westway, because back in the late 1960s it seems no one thought of building the bridges high enough to allow for the line under them to be wired up. When 313s were on the line, they had to stop to change over. 

 

When 319s were first introduced, there was a problem when a unit became gapped on DC. On regaining power, unless the driver pressed a particular button (possibly the DC button) the pantograph would go up. It would either reach its maximum height then fold itself down and lock so it could not be raised at Farrindgon or it would, and in some cases did, hit a signal gantry or bridge.

When the road bridge at West Brompton was rebuilt in the late 1960s/early 1970 it was indeed built with OHLE in mind and was rebuilt higher. Westway preceded that by about 5 years.

[melmerby]

On 25/09/2022 at 18:53, Alex TM said:

Hi folks,

 

This week I had the opportunity to make several trips on the Thameslink network, with all journeys going without a hitch.  One questions did arise:

 

     where do the units switch from overhead lines to third rail pick-up?

 

As a follow-up, I also wondered how the changeover was done as there seemed to be no loss of power nor was there any unduly long wait at any station to drop the pantograph or check the electrical supply?

Any information will be gratefully received.

 

Thanks and regards,

 

Alex.

There used to be (maybe still there) a sign at the end of the southbound line at Farringdon that said "Pant down"

[Wickham Green too]

10 hours ago, melmerby said:

... a sign a... that said "Pant down"

Good job there was only one of them ! 🤭

[St. Simon]

On 24/12/2022 at 21:54, D7666 said:

700s ASDO is intelligent enough (i.e. programmed intelligently by people who actually thought about these things) that if a 12car (FLU) stops at the 8car (RLU) marker board at a nominally 8car patform, only the front 8 cars doors are released.

 

Indeed, if a 12car stops at a nominally 7car platform (e.g. Hendon) only the front 5 are released, and so on. Automatically

Hi,

 

There’s nothing special about the ASDO on the 700s compared with anything else really, all ASDO systems automatically select the door opening pattern based on the station / platform from its onboard database, either via a GPS algorithm or via a form of an infrastructure based ASDO system, such as Packet 44 or Tracklink.

 

The only difference is that the 700s can detect the actual stopping point of the train and prevent door release for trains that stop short of the PSM.

 

However it is actually a massive pain to have an ASDO system that can automatically compensate for the stopping position, as it requires a train being stopped in an exact (within a tolerance) stopping position. If the driver gets it wrong, which does frequently happen across the country, then there is a delay in repositioning the train, where as it is quite quick on modern TMS system to alter the door release pattern from what I have been shown.
 

This sort of ASDO system requires the use of an infrastructure based system that requires Balises or Beacons on the track as a GPS system can not provide the accuracy needed to detect the exact position of the train. This means more equipment, more maintenance, more accurate surveys and makes it difficult to move stopping positions around if needed.

However, it can really only be done using ETCS Packet 44 (or the actual ETCS ASDO data packet 69) as it is the only system to provide a distance to the stopping point (D_PLATFORM + L_PLATFORM) so the train can ‘countdown’ the distance to the stopping point to allow door release.

 

Simon

Edited December 30, 2022 by St. Simon
Found the ETCS ASDO Packet No.

[St. Simon]

On 26/09/2022 at 16:07, phil-b259 said:

Yes - but due to issues with driver training the number of trains actually using ECTS/ATO (as opposed to drivers using the lineside signalling that is still present throughout) can be as low as 30% and this is particularly true when service disruption occurs.

 

Even on a good day the number of ECTS /ATO run trains only gets to the 70-80% mark

Hi,

 

Packet 44 APCO does not require the train to be operating in any ETCS Level to conduct the change-over.

 

Simon

[jim.snowdon]

3 hours ago, St. Simon said:

Hi,

 

There’s nothing special about the ASDO on the 700s compared with anything else really, all ASDO systems automatically select the door opening pattern based on the station / platform from its onboard database, either via a GPS algorithm or via a form of an infrastructure based ASDO system, such as Packet 44 or Tracklink.

 

The only difference is that the 700s can detect the actual stopping point of the train and prevent door release for trains that stop short of the PSM.

 

However it is actually a massive pain to have an ASDO system that can automatically compensate for the stopping position, as it requires a train being stopped in an exact (within a tolerance) stopping position. If the driver gets it wrong, which does frequently happen across the country, then there is a delay in repositioning the train, where as it is quite quick to modern TMS system to alter the door release pattern from what I have been shown.
 

This sort of ASDO system requires the use of an infrastructure based system that requires Balises or Beacons on the track as a GPS system can not provide the accuracy needed to detect the exact position of the train. This means more equipment, more maintenance, more accurate surveys and makes it difficult to move stopping positions around if needed.

However, it can really only be done using ETCS Packet 44 (or the other actual ETCS ASDO data packet which I can’t remember!) as it is the only system to provide a distance to the stopping point (D_PLATFORM + L_PLATFORM) so the train can ‘countdown’ the distance to the stopping point to allow door release.

 

Simon

Do we still have the ludicrous situation of there being not only no single standard SDO system but the train operators being totally reliant on the rolling stock supplier when any alterations need to be made?

 

[russ p]

88s change from diesel to electric on the move up to 20mph but starting the diesel and dropping the pan can be done at any speed 

[St. Simon]

20 minutes ago, jim.snowdon said:

Do we still have the ludicrous situation of there being not only no single standard SDO system but the train operators being totally reliant on the rolling stock supplier when any alterations need to be made?

 

 

Yes and No.

 

Yes, there is no single standard ASDO system, however, it seems that the Tracklink System or a form of ETCS Data (such as Packet 44 or 69 or just the Balise Header) are the two seemingly preferred systems. However, it doesn't matter which system is used, the TOCs will always be reliant on a single party to carry out any alterations. But even if there was a single standard system, if an ASDO system references an On-Train Database, which all the systems do to varying degrees, then the TOC will have to rely on the supplier to update it unless the supplier gives out all the tools to access the internal software databases to the TOC (which I can totally understand why they might not). If the ASDO system relies purely on data given to it from the infrastructure, then the TOC will be reliant on the Infrastructure Provider to alter the data (which I feel is the correct way of doing it).

 

Simon

[St. Simon]

26 minutes ago, russ p said:

88s change from diesel to electric on the move up to 20mph but starting the diesel and dropping the pan can be done at any speed 

 

Hi Russ,

 

Is this the Pan Raising restriction a flat 20mph or is it based on location? The rule book is that Pan Raising can be done at any location below 20mph (although this speed can vary by route but doesn't in reality), but can be done above 20mph when in a Safe Pantograph Raising Area as marked by the last two signs below:

 

 

Although it should be noted that not all of these signs are in use on Thameslink, and equally a new standard on Power Change-Over that provides further signage is being prepared.

 

Simon