RSSB looking at possible extension of 3rd rail electrification

[Domh245]

Curious to know if the anti-DC brigade, opr others, are able to share some data which compares fatal injuries from DC 3rd Rail to that of AC OHLE.

The attachment in this post is from the ORR and shows the national average risk (likelihood*severity) for OLE and third rail for different categories of 'contact' incidents. There isn't a single category of incident where the risk is lower on DC than for AC.

 

[Mikey C]

Surely there is a massive difference in the safety risk of live rails in urban environments - the massive network of 3rd rail lines criss-crossing South London - when compared to live rails running through empty countryside and small towns, where far fewer people live?

 

[Sir Felix Pole]

I think some political reality should be introduced to this debate - no government is going to authorise the billions of pounds required to re-electrify at 25kV OLE third-rail routes in London & SE whilst major inter-city and commuter lines in other parts of the country remain diesel worked. It would be a challenging sell to say the least and contrary to the 'levelling-up' agenda. I welcome, therefore, proposals for modest extensions to the third-rail to eliminate the remaining diesel islands on the Southern which can be achieved relatively quickly and economically. Similarly, it would be ridiculous to insist that the proposed Skelmersdale extension of Merseyrail be 25kV AC OLE. By my calculations Reading to Redhill (gaps), Ashford to Ore and Hurst Green to Uckfield is 82 miles, representing less than 1% of the total third-rail route mileage. How many more lives would be lost third-rail v 25kV AC OLE ? What damage are Uckfield DMUs doing pumping out fumes at Victoria?

 

[Bald Rick]

What damage are Uckfield DMUs doing pumping out fumes at Victoria?

None whatsoever.

 

[Taunton]

The attachment in this post is from the ORR and shows the national average risk (likelihood*severity) for OLE and third rail for different categories of 'contact' incidents. There isn't a single category of incident where the risk is lower on DC than for AC.

Isn't this exactly the ORR data which Walmsley showed in the Modern Railways analysis had been exaggerated/made up?

What damage are Uckfield DMUs doing pumping out fumes at Victoria?

None whatsoever.

Yes, very good . But I think a little explanation to the OP might be helpful. The Uckfield diesels run to London Bridge, not Victoria.

 

[Domh245]

Isn't this exactly the ORR data which Walmsley showed in the Modern Railways analysis had been exaggerated/made up?

I wouldn't know as I don't read MR, but it is the only data available that I'm aware of

 

[Fincra5]

The attachment in this post is from the ORR and shows the national average risk (likelihood*severity) for OLE and third rail for different categories of 'contact' incidents. There isn't a single category of incident where the risk is lower on DC than for AC.

Thanks for that link. Other than trespassers (who shouldn't be there anyway) It's hardly a massive leap.

As @Sir Felix Pole rightly says, no Government, even this one, would be insane enough to convert 3rd Rail to OHLE; whilst Electrification projects are scrapped elsewhere. IMO 3rd Rail makes total sense for Gap Filling the very low % of places on DC land where it's absent. For the rest, OHLE is the better choice.

 

[si404]

I think some political reality should be introduced to this debate - no government is going to authorise the billions of pounds required to re-electrify at 25kV OLE third-rail routes in London & SE whilst major inter-city and commuter lines in other parts of the country remain diesel worked.

But no one is suggesting that - they are suggesting that non-electrified bits might be electrified with OHLE, and eventually currently electrified bits might be converted (when the equipment need replacing anyway).

I welcome, therefore, proposals for modest extensions to the third-rail to eliminate the remaining diesel islands on the Southern which can be achieved relatively quickly and economically.

Economically is the operative word - question is whether 3rd rail is better value for money (factoring in stuff like safety, stock flexibility, etc as well as construction and operational costs).

I too welcome proposals for modest extensions to the 3rd rail to eliminate the remaining diesel islands, but we need to look and see whether 25kV AC OHLE is a better option rather than going with 3rd rail just because the rest of the area has that.

Similarly, it would be ridiculous to insist that the proposed Skelmersdale extension of Merseyrail be 25kV AC OLE.

It would be ridiculous, but that's because it's not similar!

Merseyrail to Skelmersdale is an extension of a 3rd rail electrified train service, and so if you did it with OHLE, you'd need to convert existing trains (as well as make sure you have enough units to cover the extension). That said, the 777s will have passive provision for DV capability (and they will also trial battery operation) because they have made them flexible to future extensions and don't want the stock being the tail that wags the dog for what electrification system is used.

Marshlink, Salisbury, Uckfield, North Downs, etc is the replacement of diesel services with electric ones - and so you'd be buying new units and isn't a serious issue if they have to be DV rather than 3rd rail only.

 

[swt_passenger]

3rd Rail, as its "Bottom Contact" isn't the safest admittedly but then there are X-amount of miles with it across the South East, Merseyside and 3/4th Rails on LuL. To me AC islands in a DC land make as much sense as having diesel islands. Yes there are DV units but they're all accounted for as it stands, although new stock is likely to be around by the time electrification has been posted.

One option is to explore the system used for Trams, that use (or Ground-Level Power)..

APS uses a third rail placed between the running rails, divided electrically into ten-metre rail segments with three-metre neutral sections between. Each tram has two power collection shoes, next to which are antennas that send radio signals to energise the power rail segments as the tram passes over them. At any one time, two consecutive segments under the tram will be live.

The third rail under discussion is known as “top contact”, because it’s described with respect to the part of the conductor rail the train is in contact with. It is DLR that uses a “bottom contact” third rail.

APS keeps being mentioned, but it’s been explained the technology just doesn’t scale up to the distances and far higher currents in a longer distance heavy rail network.

 

[Fincra5]

The third rail under discussion is known as “top contact”, because it’s described with respect to the part of the conductor rail the train is in contact with. It is DLR that uses a “bottom contact” third rail.

APS keeps being mentioned, but it’s been explained the technology just doesn’t scale up to the distances and far higher currents in a longer distance heavy rail network.

Sorry yes, I meant Top Contact.

 

[A0wen]

I agree. For lines like the Uckfield line, where there would be a single changeover point, I can understand the logic of doing it with AC. But for the North Downs line, where the trains would be constantly swapping from one system to another, it makes no sense.

Well actually it does - the North London Line at one time saw at least 4 changes between systems end to end from North Woolwich to Richmond - at Hackney Wick, Dalston Kingsland, Camden Road and Acton Central, until it was progressively OHL electrified with only the final stretch from Acton Central being 3rd rail now and Acton Central being the changeover point. As long as such changes can be made when at station stops, the impact is minimal.

 

[Mikey C]

But no one is suggesting that - they are suggesting that non-electrified bits might be electrified with OHLE, and eventually currently electrified bits might be converted (when the equipment need replacing anyway).

Isn't the economic problem that converting a line from DC to OHLE is a lot more expensive, and disruptive than just replacing the expired DC equipment, due to the construction costs of rebuilding bridges and tunnels...

 

[edwin_m]

As long as such changes can be made when at station stops, the impact is minimal.

Probably better though to make the changes when on the move, preferably well away from any major station. That avoids having to install dual electrification in complex areas where there is a lot of signaling equipment. So if Reading to Basingstoke was being electrified and the line on to Southampton converted to make an electric freight route, then I'd suggest also converting a few miles towards Waterloo and creating a changeover on plain line.

Isn't the economic problem that converting a line from DC to OHLE is a lot more expensive, and disruptive than just replacing the expired DC equipment, due to the construction costs of rebuilding bridges and tunnels...

I would think conversion was basically the same cost as AC electrification from scratch, as there's very little of the DC equipment that can be re-used on the AC scheme (although some might be used as spares for the rest of the DC network). I also think you should wait until we get some DC schemes costed up according to current standards before making the assumption that it will be cheaper than AC.

 

[The Ham]

Surely there is a massive difference in the safety risk of live rails in urban environments - the massive network of 3rd rail lines criss-crossing South London - when compared to live rails running through empty countryside and small towns, where far fewer people live?

Not only that but also the fact that DC land tends to have a LOT more passengers than, say, Northern WCML/ECML.

As such although the per mile rate may be higher however what about the per passenger rate?

Especially given that one of the high risk points is at stations, so therefore is have thought that the busier the station the greater the risk of someone getting hurt.

 

[edwin_m]

Not only that but also the fact that DC land tends to have a LOT more passengers than, say, Northern WCML/ECML.

As such although the per mile rate may be higher however what about the per passenger rate?

Especially given that one of the high risk points is at stations, so therefore is have thought that the busier the station the greater the risk of someone getting hurt.

Conversely if you converted a busier line from DC to AC (or chose to electrify it on AC instead of DC) then you'd be eliminating risks such as falling off the platform onto the live rail for more people. The casualties of AC are almost all trespassers, who are independent of the number of passengers and may even be more frequent on less busy lines, whereas those of DC include a substantial proportion of staff and passengers who are more likely to be found on a busier line .

 

[A0wen]

Probably better though to make the changes when on the move, preferably well away from any major station. That avoids having to install dual electrification in complex areas where there is a lot of signaling equipment. So if Reading to Basingstoke was being electrified and the line on to Southampton converted to make an electric freight route, then I'd suggest also converting a few miles towards Waterloo and creating a changeover on plain line.

My comment was in the context of the North Downs line where it was cited you'd end up changing voltages a couple of times en route - which did happen on the NLL and by making the changes at station stops it minimised the impact on journey times.

 

[edwin_m]

My comment was in the context of the North Downs line where it was cited you'd end up changing voltages a couple of times en route - which did happen on the NLL and by making the changes at station stops it minimised the impact on journey times.

Making the changes at simple stations with no switches and crossings wouldn't be much harder than making them away from a station, with some risk reduction if it wasn't done on the move. Although some services on that line are non-stop through most of that type of station.

 

[Bald Rick]

Conversely if you converted a busier line from DC to AC (or chose to electrify it on AC instead of DC) then you'd be eliminating risks such as falling off the platform onto the live rail for more people. The casualties of AC are almost all trespassers, who are independent of the number of passengers and may even be more frequent on less busy lines, whereas those of DC include a substantial proportion of staff and passengers who are more likely to be found on a busier line .

And experience shows that a trespasser is far more likely to come into contact with the third rail than the OLE.

 

[Dr Hoo]

Making the changes at simple stations with no switches and crossings wouldn't be much harder than making them away from a station, with some risk reduction if it wasn't done on the move. Although some services on that line are non-stop through most of that type of station.

If the changeover doesn't work for some reason at least it is easy to evacuate at a station, rather than the recent incident near North Pole where a trainload of overheated and frustrated pax decanted onto live third rails as investigated by the RAIB.

 

[A0wen]

Making the changes at simple stations with no switches and crossings wouldn't be much harder than making them away from a station, with some risk reduction if it wasn't done on the move. Although some services on that line are non-stop through most of that type of station.

Well the obvious changeover points would be Wokingham - electrify NDL as 25kv from there to Ash, use the current 3rd rail from there and extend it to Shalford. Then 25kv to Reigate.

It would mean a mile or so of dual electrification after Wokingham, same on approach to Ash. The other two would be in stations only so no different to Drayton Park, Farringdon or Euston.

 

[JonathanH]

Well the obvious changeover points would be Wokingham - electrify NDL as 25kv from there to Ash, use the current 3rd rail from there and extend it to Shalford. Then 25kv to Reigate.

It would mean a mile or so of dual electrification after Wokingham, same on approach to Ash. The other two would be in stations only so no different to Drayton Park, Farringdon or Euston.

I think you would try to extend the third rail to North Camp if at all possible - it would be 1 mile 17 chains from Aldershot South Junction. However, even then in the 3tph timetable one of the trains doesn't stop there.

Footbridge and level crossing at Reigate (and indeed the various crossings along the line) don't lend themselves to having the OHLE in place.

 

[Bald Rick]

I think you would try to extend the third rail to North Camp if at all possible - it would be 1 mile 17 chains from Aldershot South Junction. However, even then in the 3tph timetable one of the trains doesn't stop there.

Footbridge and level crossing at Reigate (and indeed the various crossings along the line) don't lend themselves to having the OHLE in place.

The north downs answer is batteries.

 

[GRALISTAIR]

The north downs answer is batteries.

Zero extra sparks of any type?

 

[A0wen]

I think you would try to extend the third rail to North Camp if at all possible - it would be 1 mile 17 chains from Aldershot South Junction. However, even then in the 3tph timetable one of the trains doesn't stop there.

Footbridge and level crossing at Reigate (and indeed the various crossings along the line) don't lend themselves to having the OHLE in place.

Don't see why North Camp - don't forget 3rd rail and OHLE cohabit for a similar distance out of Euston and that's a far busier, more complex arrangement than this.

On level crossings, they do exist on lines with OHLE - some are quite major roads such as the A10 at Foxton.

 

[Bald Rick]

Zero extra sparks of any type?

If the battery is sparking - run!

Don't see why North Camp - don't forget 3rd rail and OHLE cohabit for a similar distance out of Euston and that's a far busier, more complex arrangement than this.

On level crossings, they do exist on lines with OHLE - some are quite major roads such as the A10 at Foxton.

The issue with dual electrified stretches is the frequency and power of the D.C. services in (and near) the section. At Euston, 4 trains an hour of short trains; at Wokingham (say), 4 trains an hour of long trains.

Re Reigate LX, the issue is that the wires would have to be high for the crossing, which means that the bridge would have to be lifted. Quite a bit. But it’s not a deal breaker; the deal would already be broken by the sheer cost of OLE compared to the alternative (batteries).

 

[Fincra5]

The north downs answer is batteries.

Maybe when battery power is actually feasible for modern EMUs (well BEMUs) with A/C etc..

Same could be said for the Marshlink but the tech isn't good enough vs 3rd Rail for that section.

Re: Trespassers, perhaps the answer is education to the dangers of the railway. And the fact they shouldn't be there anyway...

 

[A0wen]

Re: Trespassers, perhaps the answer is education to the dangers of the railway. And the fact they shouldn't be there anyway...

Problem is 3rd rail is a hazard to rail employees who have to work close to it.

Having an exposed high voltage power supply, unprotected, unshielded at ground level is a liability.

If you were building railways from scratch today you'd never get safety approval for such a method of electrification. Just because 100 years ago we took a more cavalier view of health and safety doesn't mean we should persist with such liabilities today when we ought to know better.

 

[Mikey C]

Probably better though to make the changes when on the move, preferably well away from any major station. That avoids having to install dual electrification in complex areas where there is a lot of signaling equipment. So if Reading to Basingstoke was being electrified and the line on to Southampton converted to make an electric freight route, then I'd suggest also converting a few miles towards Waterloo and creating a changeover on plain line.

I would think conversion was basically the same cost as AC electrification from scratch, as there's very little of the DC equipment that can be re-used on the AC scheme (although some might be used as spares for the rest of the DC network). I also think you should wait until we get some DC schemes costed up according to current standards before making the assumption that it will be cheaper than AC.

As DC exists already, unless a government says DC is banned and hands the railways 100bn or whatever to replace it all with OHLE, I cannot see a scenario where it will make economic sense for the railways to convert all the DC network to AC.

Imagine the cost of converting Clapham Junction and its environs to OHLE, it would be horrendous

 

[GRALISTAIR]

As DC exists already, unless a government says DC is banned and hands the railways 100bn or whatever to replace it all with OHLE, I cannot see a scenario where it will make economic sense for the railways to convert all the DC network to AC.

Imagine the cost of converting Clapham Junction and its environs to OHLE, it would be horrendous

There were quite a few threads on it at one time

https://www.railforums.co.uk/threads/suggestion-conversion-of-former-southern-region-dc-to-ac.131188/

 

[GRALISTAIR]

I remembered this excellent document from Network Rail on DC to AC Conversion

https://www.imeche.org/docs/default-source/events/Sir_Seymour_Biscoe_Tritton_Lecture-_DC_to_AC_Conversion_by_Steve_Yianni.pdf?sfvrsn=0