GWR to lease ‘tri-mode’ class 769 multiple units from Porterbrook

[phil-b259]

14 hours ago, Zomboid said:

And 25kV doesn't need so many substations (which often need land purchase) or 3 phase distribution.

 

Substations can cause sighting issues, though obviously not as many as overhead line masts.

 

What a strange notion.

 

Quite obviously a substation has a fair degree of wiggle room as to where its actually located and can easily be shifted back and forth by a 1/4 mile or so at the planning stages to keep it out of the way of signals. Land take is also not a big issue - the 'raft' designs used from the mid 1930s being pretty compact structures with many simply slotted within the existing railway boundary fences and no land purchases needed at all.

 

OLE supports are a different mater because they need to be fairly close together to hold up the wires!

Edited August 6, 2021 by phil-b259

[Zomboid]

15 minutes ago, phil-b259 said:

Quite obviously a substaion has a fair degree of wiggle room as to where its actually located and can easily be shifted back and forth by a 1/4 mile or so at the planning stages to keep it out of the way of signals.

Not as much as you might think on DC. Spacing between buildings is typically around 2km, so a 1/4 mile (400m) is actually a significant distance. Whilst the HVAC switchgear and rectifiers can be moved around a bit, the DC switchgear needs to be pretty close to the section gaps, or the cable length starts to create problems with voltage regulation and requires more restrictive protection. It depends a lot on the route in question though.

[Zomboid]

36 minutes ago, DY444 said:

Uckfield, whilst there might be entirely sensible reasons for doing it as AC, I simply don't buy the idea that AC and DC would be the same cost.  It just doesn't pass the sniff test in an age where people are saying that not straightforward but eminently do-able structures like the Leicester bridge and Standedge tunnel are too difficult and too expensiv

I don't know how it stacks up now, but pre GWML it was thought that they would be about the same per single track km.

 

Obviously we've now done a bunch of 25kV projects so those figures might be more accurate, but there's nothing much to go on for a new electrification on DC at the moment. Renewals and enhancements can give some guidance, but only to a certain point.

 

The reality is that it's not a simple one figure comparison. Bridge alterations are expensive, but that's not so important if the route in question doesn't have many, or if some gauge clearance project has been through and done the job already. 25kV AC can supply more power than 3rd rail DC, and at higher speeds. Immunisation requirements depend on what you're starting from, and that's not a constant.

 

AC on the Uckfield line would be a bit silly for a number of reasons.

[phil-b259]

10 minutes ago, Zomboid said:

 

AC on the Uckfield line would be a bit silly for a number of reasons.

 

The biggest issue has nothing to do with the railways though! Its the fact that rural / inland East Sussex traditionally lacked heavy industry or large urban conurbations. As such the national grid is pretty weak and in no position to provide feeders to the Uckfield line without some pretty hefty investment.

 

Therefore the most likely solution (particularly in an age where the DfT are obsessed with 'Bionic Duckweed' or batteries being the future)  is some sort of hybrid train that uses conductor rail north of Hurst Green and one of those alternative power sources south of there - maybe with some sort of 'charging 3rd rail' facility installed at Uckfield to give a boost during layovers

Edited August 6, 2021 by phil-b259

[DY444]

2 hours ago, Zomboid said:

I don't know how it stacks up now, but pre GWML it was thought that they would be about the same per single track km.

 

Obviously we've now done a bunch of 25kV projects so those figures might be more accurate, but there's nothing much to go on for a new electrification on DC at the moment. Renewals and enhancements can give some guidance, but only to a certain point.

 

The reality is that it's not a simple one figure comparison. Bridge alterations are expensive, but that's not so important if the route in question doesn't have many, or if some gauge clearance project has been through and done the job already. 25kV AC can supply more power than 3rd rail DC, and at higher speeds. Immunisation requirements depend on what you're starting from, and that's not a constant.

 

AC on the Uckfield line would be a bit silly for a number of reasons.

 

I don't think anyone is proposing DC for anything other than infills or short extensions so the undisputed ability of AC to deliver more power, more efficiency and be suitable for high speeds is largely academic for the lines in question. 

 

AC to Uckfield is indeed silly but Gibb, clearly under pressure from the "we don't care what it costs because it isn't our money" ORR, undermined the credibility of his entire report by saying otherwise.

[96701]

I doubt that any 3rd rail top contact systems will be allowed because they are against the Electricity at Work Regulations with bare live conductors being at ground level.

[AMJ]

For units with range extending batteries it will be feasible to have stretches of electrification in stations where a unit will be able to boost the batteries.  Similar to the electric buses in many cities, some I have seen, use trolleybus style wires between 2 lamp posts and a bus sat charging at the terminus.

 

Charging power could easily be provided where the grid infrastructure permits.

[Artless Bodger]

An interesting discussion. Could DC infill be achieved with OLE? The original SR electric locos and the E5000s had pantographs for use in wired yards, admittedly the yard wiring was only trolley wire type, and the NER also had a mix of 3rd rail and OLE DC (as did the French). I accept the DC OLE has to be heavier than AC to cope with the currents, but for relatively short distances such as to Uckfield, or across the Marsh perhaps it would be acceptable? Most Electrostars have a pan well, though I may be underestimating the work needed to fit a DC pan and connections to the exisitng traction equipment. I believe also it is no longer necessary to have separate apns for each supply type, the on board system checks the voltage / frequency before reconnecting. Please correct me if I'm wrong.

 

If I remember correctly, the EGIP electrification had to be redesigned in places due to changes in the electricity at work regulations, and I have seen some photos of OLE masts located outside the railway boundary as a consequence, with excessive security provision to stop the terminally inclined from climbing the things.

[Artless Bodger]

21 minutes ago, 96701 said:

I doubt that any 3rd rail top contact systems will be allowed because they are against the Electricity at Work Regulations with bare live conductors being at ground level.

What about the 'Alimentation par sol' (if I've spelled it right), that some French trams use, only the contacts covered by the vehicle are energised as I understand it, would that comply, and could it be used in modified form for 3rd rail? I think a charging rail for the District stock battery conversion trial used something similar with a trickle charged battey bank on land to dump charge into the train battery?

[009 micro modeller]

1 hour ago, Artless Bodger said:

An interesting discussion. Could DC infill be achieved with OLE? The original SR electric locos and the E5000s had pantographs for use in wired yards, admittedly the yard wiring was only trolley wire type, and the NER also had a mix of 3rd rail and OLE DC (as did the French). I accept the DC OLE has to be heavier than AC to cope with the currents, but for relatively short distances such as to Uckfield, or across the Marsh perhaps it would be acceptable? Most Electrostars have a pan well, though I may be underestimating the work needed to fit a DC pan and connections to the exisitng traction equipment. I believe also it is no longer necessary to have separate apns for each supply type, the on board system checks the voltage / frequency before reconnecting. Please correct me if I'm wrong.

 

If I remember correctly, the EGIP electrification had to be redesigned in places due to changes in the electricity at work regulations, and I have seen some photos of OLE masts located outside the railway boundary as a consequence, with excessive security provision to stop the terminally inclined from climbing the things.

 

Wasn’t 750V DC overhead, as you describe, suggested somewhere a few years ago as a way of cheaply electrifying self-contained local railways? Obviously this is also the system used by most of the UK’s light rail/tram systems. Although I’m not sure that Network Rail would want to introduce this as a continuation of existing third rail electrification, particularly as it requires modifications to the stock to make it dual-equipped etc. One advantage though is that, assuming they were built to appropriate standards, if future AC conversion eventually took place the masts could be reused (see Manchester, where on some lines the same masts have been used first for 1500V DC (Woodhead and related lines), then 25kV AC, then 750V DC (Metrolink)).

[DY444]

1 hour ago, 96701 said:

I doubt that any 3rd rail top contact systems will be allowed because they are against the Electricity at Work Regulations with bare live conductors being at ground level.

 

Except there are hundreds and hundreds of route miles of third rail across the South East from the Kent Coast in the east to Weymouth in the west which is going to be around for a very long time indeed irrespective of what the regs say.  Hurst Green to Uckfield is 24 miles; the gaps between Wokingham and Ash Jn and Shalford Jn and Reigate together are 25 miles all in relatively rural areas.  That's 49 miles more which is a tiny increase both to the total and to the total risk.   Also sidings, yards and urban areas carry a proportionately higher risk so the actual increase in risk is likely to be less than the increase in third rail mileage.

[96701]

9 minutes ago, DY444 said:

 

Except there are hundreds and hundreds of route miles of third rail across the South East from the Kent Coast in the east to Weymouth in the west which is going to be around for a very long time indeed irrespective of what the regs say.  Hurst Green to Uckfield is 24 miles; the gaps between Wokingham and Ash Jn and Shalford Jn and Reigate together are 25 miles all in relatively rural areas.  That's 49 miles more which is a tiny increase both to the total and to the total risk.   Also sidings, yards and urban areas carry a proportionately higher risk so the actual increase in risk is likely to be less than the increase in third rail mileage.

I'm not saying the minor extension of top contact conductor rail shouldn't happen, just that it probably won't because of legal matters.

[phil-b259]

2 hours ago, DY444 said:

 

Except there are hundreds and hundreds of route miles of third rail across the South East from the Kent Coast in the east to Weymouth in the west which is going to be around for a very long time indeed irrespective of what the regs say.  Hurst Green to Uckfield is 24 miles; the gaps between Wokingham and Ash Jn and Shalford Jn and Reigate together are 25 miles all in relatively rural areas.  That's 49 miles more which is a tiny increase both to the total and to the total risk.   Also sidings, yards and urban areas carry a proportionately higher risk so the actual increase in risk is likely to be less than the increase in third rail mileage.

 

You miss the point.

 

The ORR have to give a derogation from standard for the 3rd rail which exists to remain precisely because it is illegal under virtually all regulations which apply to electricity in the workplace - and yes the railway IS the workplace for hundreds of P-way, S&T types!

 

This derogation ONLY covers the existing mileages on the basis that conversion to OLE is not practical (Extra platforms, sidings or rearranged track work is deemed to be part of the existing installed mileage).

 

This is no different in principle from Level crossings where those which exist are tolerated (but must be continually assessed and upgraded)  but NO new ones are permitted (greatly increasing the costs of projects like EastWest Rail or the Borders Railway) to be installed.

 

 

[phil-b259]

4 hours ago, Artless Bodger said:

What about the 'Alimentation par sol' (if I've spelled it right), that some French trams use, only the contacts covered by the vehicle are energised as I understand it, would that comply, and could it be used in modified form for 3rd rail? I think a charging rail for the District stock battery conversion trial used something similar with a trickle charged battey bank on land to dump charge into the train battery?

 

Discontinuous electrification (i.e. short conductor rail sections which are only live when a train is on them) has been touted before as a potential solution and the ORR have indicated they could run with this provided the energised lengths are kept as short as possible.

 

The problem is that for compatibility reasons such conductor rail would look exactly the same as the regular, permanently energised stuff we have at present and you then massively increase the risk of a trespasser not realising this and stepping on it 'because the con rail is dead' only to find out it isn't.

 

As such its only really going to be a potential solution at termi where trains have longish layovers and the con rail can be kept short (a train length) - although in truth it would probably be more desirable to have it live at all times.

 

 

[phil-b259]

4 hours ago, Artless Bodger said:

An interesting discussion. Could DC infill be achieved with OLE?

 

Yes it could - once you put the power source up in the air and out of reach it becomes compliant with the Electricity at Work regulations, etc.

 

Conceptually therefore a 750V OLE infill would work quite well as the supply side of things would be identical to that needed for conductor rail rather than AC

 

The issues are more that you would need a new train fleet (the conversion work on the Electrostars would be pretty expensive - its not as though they are pre-wired for it like they are for 25KV)  - and if you are doing that then going for a bi mode (con rail + battery / hydrogen / diesel / bionic duckweed) would probably come out cheaper than new train AND all the electrification infrastructure.

[DY444]

9 minutes ago, phil-b259 said:

 

You miss the point.

 

The ORR have to give a derogation from standard for the 3rd rail which exists to remain precisely because it is illegal under virtually all regulations which apply to electricity in the workplace - and yes the railway IS the workplace for hundreds of P-way, S&T types!

 

This derogation ONLY covers the existing mileages on the basis that conversion to OLE is not practical (Extra platforms, sidings or rearranged track work is deemed to be part of the existing installed mileage).

 

This is no different in principle from Level crossings where those which exist are tolerated (but must be continually assessed and upgraded)  but NO new ones are permitted (greatly increasing the costs of projects like EastWest Rail or the Borders Railway) to be installed.

 

 

 

I'm aware of all of that and don't miss the point at all.  The ORR takes that line because it has no choice but the fact is that literally nobody that would be working on North Downs or Uckfield be they train crew, S&T, PW or whoever doesn't already work on third rail lines (and in the case of S&T and PW probably spends most of their time on them).  The additional risk is minimal and it's just the ORR throwing their weight about.  It's an argument cut from the same cloth that says ole clearances have to be increased because of selfie sticks and balloons as if people don't have those things at stations on the huge mileage of lines fitted with ole before EGIP.  It's a stance taken because the ORR can take it not because it makes sense.

[RJS1977]

The Electricity at Work Regulations went on the statute book in 1989.

 

They didn't prevent the building of the Jubilee Line Extension, or the Eurostar platforms at Waterloo (or indeed the Northern Line extension, although that is wholly underground). So I don't see why they should affect any otehr 3rd rail electrification schemes.

[DY444]

6 minutes ago, phil-b259 said:

 

Yes it could - once you put the power source up in the air and out of reach it becomes compliant with the Electricity at Work regulations, etc.

 

Conceptually therefore a 750V OLE infill would work quite well as the supply side of things would be identical to that needed for conductor rail rather than AC

 

The issues are more that you would need a new train fleet (the conversion work on the Electrostars would be pretty expensive - its not as though they are pre-wired for it like they are for 25KV)  - and if you are doing that then going for a bi mode (con rail + battery / hydrogen / diesel / bionic duckweed) would probably come out cheaper than new train AND all the electrification infrastructure.

 

What diameter overhead conductor would you need to supply the current for a 10 car electrostar at 750V?  Something akin to a scaffolding pole probably - totally impractical I should think.

[DY444]

1 minute ago, RJS1977 said:

The Electricity at Work Regulations went on the statute book in 1989.

 

They didn't prevent the building of the Jubilee Line Extension, or the Eurostar platforms at Waterloo (or indeed the Northern Line extension, although that is wholly underground). So I don't see why they should affect any otehr 3rd rail electrification schemes.

 

and the West London Line, ELL and Tonbridge to Redhill

[phil-b259]

19 minutes ago, DY444 said:

 

What diameter overhead conductor would you need to supply the current for a 10 car electrostar at 750V?  Something akin to a scaffolding pole probably - totally impractical I should think.

 

That is of course the achilleas heal - but much depends on train lengths and weights. I point you to Manchester, Sheffield or Croydon trams which have some significant gradients yet still cope with what appears to be a regular sized conductor cable diameter.

 

Given the North Downs is a 3 / 4 car railway I think you could do something similar - possibly with some tram - train style rolling stock to keep the trains as light as possible.

 

The Uckfield line is more of an issue as 10 car DMUs (equivalent to 12 Car Electrostarts) operate in the peaks - but if you combined a 750V OLE with batteries which get charged by the con rail north of Hurst Green then you wouldn't need such a beefy overhead conductor.

 

 

Edited August 6, 2021 by phil-b259

[phil-b259]

5 minutes ago, DY444 said:

 

and the West London Line, ELL and Tonbridge to Redhill

 

We live in different times - there was no ORR in the early 1990s and BR was left to do what it thought best.

 

These days the advancement of the legal profession into virtually all areas of life means different considerations apply.

 

Put it this way if a trespasser got electrocuted by a new 3rd rail installation today you can bet your bottom dollar a Lawyer would be willing to start taking the infrastructure owner to court and most likely win!

[phil-b259]

2 hours ago, RJS1977 said:

The Electricity at Work Regulations went on the statute book in 1989.

 

They didn't prevent the building of the Jubilee Line Extension, or the Eurostar platforms at Waterloo (or indeed the Northern Line extension, although that is wholly underground). So I don't see why they should affect any otehr 3rd rail electrification schemes.

 

Firstly the new international platforms at Waterloo would count as a modification to the existing 3rd rail mileage and just as with the modifications a couple of years ago to the track layout or the new platform 0 at Redhill are permitted by the ORRs derogation.

 

The nine elms chord is a better example to have cited as that was technically a brand new piece of track, however its less than a mile  - rather different from 25 miles of new electrification.

 

Secondly, over half of of the Jubilee Line extension is in tunnels - and the surface section is heavily fenced in plus lacks ANY level crossings (be they footpaths or roads) and so making it very difficult to Trespass on it. As you note the Northern Line extension is wholly underground and thus virtually impossible for the public to access.

 

Thirdly, and its perhaps the most important consideration, the power gets turned off overnight and whenever staff are on the tracks on London Underground infrastructure,  thus their working practices do in fact fully comply with the regulations! A very different situation from the national rail network where staff are expected to work around it live unless the task they are doing specifically needs an isolation.

Edited August 6, 2021 by phil-b259

[Artless Bodger]

That puts us back in the situation where nobody has to take responsibility for their own actions, however stupid. It always strikes me how many railway lines outside the UK have no fencing and in some cases run on road margins with nothing substantial to keep errant drivers off the track. 

 

On the Tyne and Wear Metro I notice that in some places the catenary support wire seems to be in effect a parallel second contact wire (e.g. along the Benton - South Gosforth stretch), I'm not sure if this is due to tight clearance, but presumably would double the current carrying capacity on that stretch?

Edited August 6, 2021 by Artless Bodger
Spelling, insensitive comment removed.

[St. Simon]

I think we’ve drifted well away from the topic at hand, Class 769/9s…

 

Simon

[Northmoor]

1 hour ago, Artless Bodger said:

That puts us back in the situation where nobody has to take responsibility for their own actions, however stupid. In a sane world anyone trespassing gets what they deserve. It always strikes me how many railway lines outside the UK have no fencing and in some cases run on road margins with nothing substantial to keep errant drivers off the track. 

 

On the Tyne and Wear Metro I notice that in some places the catenary support wire seems to be in effect a parallel second contact wire (e.g. along the Benton - South Gosforth stretch), I'm not sure if this is due to tight clearance, but presumably would double the current carrying capacity on that stretch?

Until one of your relatives/friends gets electrocuted.  If someone is hit by a train because they wander onto the track, does the driver who is absolutely powerless to avoid them, get what they deserve as well?

 

I agree about the fencing requirements in the UK being extreme compared to the rest of Europe, but I don't know how many non-passengers are killed on European railways.  Last time I saw statistics, the UK now has pretty much the safest railway in the world.  Should we decide it's acceptable to kill a few more, for everyone's convenience?