Manchester Piccadilly OHLE question.

[nexusdj]

Looks like a wired crossover though unusable for electric traction you can see it better in these other pics . 

 

David Ford pics from 1971 : https://www.flickr.com/photos/davidwf2009/5537874243/sizes/h/

https://www.flickr.com/photos/davidwf2009/5537880309/sizes/h/

1972 further back : https://www.flickr.com/photos/davidwf2009/33529718463/sizes/h/

 

The crossover wire continues its run up the down DC line and the down DC wire becomes the crossover wire for the last part of the crossover .

 

 

[DY444]

23 hours ago, pendlerail said:

I am sure I have read somewhere that two platforms were dual voltage switched over by the signaller 5 & 6 from memory

 

Another urban myth I believe.  As has been illustrated there was no path for the pantograph across the insulators.  The list of operational headaches and scope for expensive mistakes, fires etc far outweighs any conceivable operational benefit.  The problem with the platforms in question at Piccadilly being dead ends is that it affects the approach lines too not just the platform(s).  Which brings us to ...

 

18 hours ago, Zomboid said:

Switched sections of OLE do exist, though not in the UK. I believe Aachen has some platforms which can be energised at different voltages, but quite how the control system for that works I've no idea.

 

I see that Aachen is a through station.  That makes it a much more straight forward proposition to my mind.  I presume in a typical situation the lines at each end will be on different systems and each platform has its own individual isolated section of ole which can be switched to be one system or the other.  Through train runs in on one system, stops, drops pan, ole on the platform is changed over, pan raised, train departs on the other system.  Obviously if the train is reversing in the platform then no switch over is required. 

 

Such a system obviously requires co-ordination between train crew and whoever is responsible for doing the changeovers but in Europe they seem rather more prepared to trust the operational staff than we do (no APC, pan drop balise systems etc).     

Edited July 1, 2021 by DY444

[iands]

23 hours ago, pendlerail said:

I am sure I have read somewhere that two platforms were dual voltage switched over by the signaller 5 & 6 from memory

Highly unlikely, the signaller has the responsibility of operating the Signalling only. The OLE is controlled by the ECRO. 

[woodenhead]

If there had ever been a dual voltage option on Platform 5 & 6 then there would be photographic evidence.

 

Manchester Piccadilly has been heavily photographed since the 1950s, especially since becoming Piccadilly and no-one has ever shown anything other than dc electrics in 1-4.

 

Maybe people suspected it because 5+6 got a lot of traffic off Ashburys from the Peak district plus the Harwich Boat train and so began a legend.

 

The LNE side of London Road only had three platforms so why would BR had increased it to six lines in Piccadilly especially knowing the premier route was AC, the DC route was non standard and going to see less traffic long term.

[Titan]

3 hours ago, nexusdj said:

Looks like a wired crossover though unusable for electric traction you can see it better in these other pics . 

 

David Ford pics from 1971 : https://www.flickr.com/photos/davidwf2009/5537874243/sizes/h/

https://www.flickr.com/photos/davidwf2009/5537880309/sizes/h/

1972 further back : https://www.flickr.com/photos/davidwf2009/33529718463/sizes/h/

 

The crossover wire continues its run up the down DC line and the down DC wire becomes the crossover wire for the last part of the crossover .

 

 

 

 

8 hours ago, Clive Mortimore said:

I think the insulators we are looking at are normal ones for a out of running wire going to a terminating point or tensioning weight.

 

Similar ones at Chelmsford

 

 

 

It is an unusual, possibly even unique arrangement albeit made up of standard components, like the ones in the top wire in Clive's photo.

 

What you have is a set of those insulators, then a short earthed section of wire - you can see the earth wire jumper going to the structure in the Manchester pictures, then another set of those insulators.

 

So you have something like  ---|||---|||--- with the bit in the middle earthed, and then repeated in the contact wire.  It is like a very short neutral section - the bit in the middle being neutral/earth and certainly not intended for a pantograph to pass over!

 

Edited July 1, 2021 by Titan

[Clive Mortimore]

4 hours ago, nexusdj said:

Looks like a wired crossover though unusable for electric traction you can see it better in these other pics . 

 

David Ford pics from 1971 : https://www.flickr.com/photos/davidwf2009/5537874243/sizes/h/

https://www.flickr.com/photos/davidwf2009/5537880309/sizes/h/

1972 further back : https://www.flickr.com/photos/davidwf2009/33529718463/sizes/h/

 

The crossover wire continues its run up the down DC line and the down DC wire becomes the crossover wire for the last part of the crossover .

 

 

Hi Nexusdj

 

Looking at the three photos you posted today, I stand very corrected, the insulator is between the two systems. If any signalman was to send a electric loco or EMU across the crossover there would be one 'ell of a mess.

 

Very interesting, plus every day is a school day.

[jamie92208]

And here is the 2017 equivalent. Between Angouleme and Poitiers where TGV's from Angouleme access the High Speed line towards Paris. The classic lines are 1500V Dc and the LGV 25 KV AC. You can see the white insulator in the contact wire and the sign for the drivers that they are entering DC territory.

Heading towards the LGV the drivers see this.

In practice the pantographs come down a good quarter of a mile before the changeover and the new one isn't raised until quarter of a mile after when a double TGV is well clear and at that point there is a quite steep ramp up towards the LGV.

 

Jamie

 

Edited April 20, 2022 by jamie92208

[jim.snowdon]

17 hours ago, nexusdj said:

There are a few pics on Flickr taken at Ardwick from various photographers showing the crossover between the DC and AC fitted lines and there's a double set of insulators on both the contact and catenary wires . Would of made a mess if a pantograph had tried to run along that section of catenary !

 

Tony Walmsley image taken 1983   : https://www.flickr.com/photos/75514026@N03/23258605816/sizes/h/

 

Note also the additional mesh partition on each of the gantries between the two systems . 

 

I would suspect that the wire was only carried over the crossover in order to provide a convenient run out/run in for another wire run on the AC side. Easier than providing two separate anchors.

 

[jim.snowdon]

6 hours ago, Clive Mortimore said:

Hi Nexusdj

 

Looking at the three photos you posted today, I stand very corrected, the insulator is between the two systems. If any signalman was to send a electric loco or EMU across the crossover there would be one 'ell of a mess.

 

Very interesting, plus every day is a school day.

One of the three photographs shows the whole of the crossover, and the wire is also insulated between the up and down DC lines (as would be normal for sectioning) but with ordinary inline insulators before then running out above the up DC wire to the anchor (I'm assuming that DC trains were Down to Manchester). It's also interesting to compare the flat knuckle intersection of the wires on the DC side with the simple 'one wire over the other' intersection on the AC side, occasioned by the different pantograph bow profiles on the DC stock compared to the AC stock.

 

[russ p]

I can't imagine them being switchable as how would the driver know what system was in use

[The Stationmaster]

8 hours ago, russ p said:

I can't imagine them being switchable as how would the driver know what system was in use

Trust in those responsible for doing the changeover?     Or - far better and as seen in the film I linked, an illuminated indicator showing which voltage was in use.

[russ p]

6 hours ago, The Stationmaster said:

Trust in those responsible for doing the changeover?     Or - far better and as seen in the film I linked, an illuminated indicator showing which voltage was in use.

 

I don't think there were ever any things like that over here, unfortunately as BR would have probably made a nice electromechanical one!

I wouldn't have thought there was any physical connection between the two systems at Manchester and any wrong routing would mean a dewiring incident 

[Michael Hodgson]

Most signalbox reminder appliances (lever collars) were a simple lump of metal which when placed over the lever handle stopped you from operating the catch handle to pull the lever in question.  They were used to protect stretches of line which were obstructed or under an engineer's possession etc and the rules specified certain situations when they must be used.  They were often lettered with a message such as "Workmen" or "Stop and think".  More modern boxes had different designs with the same purpose - for example a magnetic cover for a push-button in a NX panel.

 

Some were lettered "Blocked to electric trains" , but were fitted with a flap which you could lift to pull the lever if the train was diesel hauled.  They could be used to remind signalmen not to admit electric trains to yards and sidings which weren't wired.

 

 

 

There were lineside signs for the benefit of drivers too ....

https://www.flickr.com/photos/geoffsimages/13586635403/

 

Edited July 2, 2021 by Michael Hodgson

[Edwin_m]

2 hours ago, Michael Hodgson said:

Most signalbox reminder appliances (lever collars) were a simple lump of metal which when placed over the lever handle stopped you from operating the catch handle to pull the lever in question.  They were used to protect stretches of line which were obstructed or under an engineer's possession etc and the rules specified certain situations when they must be used.  They were often lettered with a message such as "Workmen" or "Stop and think".  More modern boxes had different designs with the same purpose - for example a magnetic cover for a push-button in a NX panel.

 

Some were lettered "Blocked to electric trains" , but were fitted with a flap which you could lift to pull the lever if the train was diesel hauled.  They could be used to remind signalmen not to admit electric trains to yards and sidings which weren't wired.

 

 

 

There were lineside signs for the benefit of drivers too ....

https://www.flickr.com/photos/geoffsimages/13586635403/

 

These were also used under Rule 55 when a train was stopped on the running line and not protected by any other means.  Failure to do this could (and sometimes did) cause a catastrophic accident, so reliance was placed on lever collars for far more than preventing a damaged pantograph and wire and some operational embarrassment.  

[DY444]

23 hours ago, russ p said:

I wouldn't have thought there was any physical connection between the two systems at Manchester and any wrong routing would mean a dewiring incident 

 

Well there were definitely crossovers between the lines on the two systems.  Probably the most remembered use of these was for the transferring of 506s between the DC platforms at Piccadilly and Longsight after Reddish depot closed in the last years of the DC.    

Edited July 3, 2021 by DY444

[russ p]

Just now, DY444 said:

 

Well there were definitely crossovers between the lines on the two systems.  Probably the most remembered use of these was for the transferring of 506s between the DC platforms at Piccadilly and Longsight after Reddish depot closed in the last years of the DC.    

 

Sorry I meant physical connections between the OLE obviously with a neutral separating the two

[DY444]

38 minutes ago, russ p said:

 

Sorry I meant physical connections between the OLE obviously with a neutral separating the two

 

The OLE was connected.  Why is the question. 

 

I've now looked at the Piccadilly track plan at the time of the opening of the AC.  All three of the connections between the systems had relatively complex S&C either on the actual connection itself or very close by so the explanation offered earlier that physically connecting the two via the hefty insulators made it easier to provide the wire runs across those S&C elements seems the most plausible to me.  As all the original DC structures were replaced with new structures shared by the two systems then it might even be the case that the topology of the wire runs was designed as though it was a single system with the insulators placed at the transition points.  Maybe BR had half an eye on making it easier at some future point to convert the DC to AC as was about to happen on the GE and ultimately happened at Piccadilly?   Designing it as a homogenous system would facilitate that.

Edited July 3, 2021 by DY444

[jamie92208]

1 hour ago, DY444 said:

 

The OLE was connected.  Why is the question. 

 

I've now looked at the Piccadilly track plan at the time of the opening of the AC.  All three of the connections between the systems had relatively complex S&C either on the actual connection itself or very close by so the explanation offered earlier that physically connecting the two via the hefty insulators made it easier to provide the wire runs across those S&C elements seems the most plausible to me.  As all the original DC structures were replaced with new structures shared by the two systems then it might even be the case that the topology of the wire runs was designed as though it was a single system with the insulators placed at the transition points.  Maybe BR had half an eye on making it easier at some future point to convert the DC to AC as was about to happen on the GE and ultimately happened at Piccadilly?   Designing it as a homogenous system would facilitate that.

That would make a lot of sense. On the photos the insulators on the DC lines all appear to be hefty enough for 25Kv.

 

Jamie

[Grovenor]

If the contact wire was omitted on the linking crossovers, then any electric train accidentally taking the route would have the pan rise up into the overhead likely causing extensive damage to both pan and OHLE, not something you want in a busy station throat. In fact my recollection was that in line contact wire insulators were fitted, I am surprised to see the catenary style insulators in the pics as these also represent a hazard should a pan run into them. Without the damage scenario the electrical protection would be activated pulling out the breakers, blowing fuses etc and the train could be rescued without needing days of rewiring.

[jim.snowdon]

It all ultimately comes down to the signaller knowing (as it will be writ large in the box instructions) that you do not route an electric train, of either sort, across said crossovers. It is even possible that there were no main aspects for the routes, only subsidiary aspects, ie GPLs, which would further alert an electric driver by being totally unexpected.

 

One thing that you certainly would not want is a 506 being accidentally connected to 25kV, given that that voltage is a long way outside any of its electrical insulation.

 

[jim.snowdon]

7 hours ago, DY444 said:

The OLE was connected.  Why is the question. 

To simplify the wire runs and reduce the number of anchor points required, I suggest. (Not the sort of lateral thinking that would be indulged in today, I suspect.)

[The Stationmaster]

1 hour ago, jim.snowdon said:

It all ultimately comes down to the signaller knowing (as it will be writ large in the box instructions) that you do not route an electric train, of either sort, across said crossovers. It is even possible that there were no main aspects for the routes, only subsidiary aspects, ie GPLs, which would further alert an electric driver by being totally unexpected.

 

One thing that you certainly would not want is a 506 being accidentally connected to 25kV, given that that voltage is a long way outside any of its electrical insulation.

 

There were definitely main aspect routes, in both directions, between the two sides at London Road/Piccadilly.  All the GPLs which had routes to either side had stencil route indicators which showed 'E' for any route towards the dc side of things.

[Zomboid]

5 hours ago, jim.snowdon said:

To simplify the wire runs and reduce the number of anchor points required, I suggest. (Not the sort of lateral thinking that would be indulged in today, I suspect.)

It also gives something for the pan to run along if it is mis-routed. If it were to come off the wires and shoot skywards before crashing into the side of the other system equipment the results are likely to be much uglier than if it's just an electrical fault where a train needs to be dragged out.

[Grovenor]

1 hour ago, Zomboid said:

It also gives something for the pan to run along if it is mis-routed. If it were to come off the wires and shoot skywards before crashing into the side of the other system equipment the results are likely to be much uglier than if it's just an electrical fault where a train needs to be dragged out.

What I said above, but a pan hitting those insulators could be equally ugly as something would almost certainly break, so why was it not a contact wire insulator the pan could run under. Not that there is anyone who knows around to answer!

[The Stationmaster]

10 hours ago, Grovenor said:

What I said above, but a pan hitting those insulators could be equally ugly as something would almost certainly break, so why was it not a contact wire insulator the pan could run under. Not that there is anyone who knows around to answer!

Two questions I think -

1. Were short contact wire insulators available at that time?  (I remember considerable noise being made later in the 1960s when BR developed a new fibre glass cntact wire insulator which was much shorter than those previously used (but I don't know the lengths of either).  And,

2. If a pan went past an insulator without damaging either itself or the insulator what happened next?  Presumably as the contact wire rose to terminate on a gantry the pan would also rise and hit the gantry (which might also be carrying - albeit insulated - 25kv  overhead) and might leave part of the pan to carry on into the territory of the other voltage. 

 

Which leaves a supplementary point that as there would probably be insufficient time for the pan to auto lower as it went over-height some sort of collision between it and 'something' - structure, insulator or whatever was inevitable in the event of mis-routing.  

For the past 30 or so years such an event would be subject to a risk assessment process the outcome of which would help to decide the mitigation.  But back in the 1960s that sort of assessment would almost inevitably be made in an individual's mind or during discussion at a planning etc meeting or when the old boy sitting in the corner at a meeting suddenly piped up with 'what if?'   I doubt there is any surviving documentation to say what was, or wasn't, in mind when the two systems were being planned to work alongside each other in Manchester.