My suggestion to remove third rail as a priority

[swt_passenger]

I may be mistaken, but I thought top contact 3rd rail operated under a derogation and no new installations were permitted?

Extensions and infill are permitted, and can be quite long. For example the original electrification RUS allowed for the possibility of both Basingstoke to Salisbury, and the North Downs being DC electrified, and there were other proposals too...

 

[LBSCR Times]

One downside of the third rail is when the emergency services go on the track, due to an incident, and the traction current is discharged over a large area, due to having abutting sections, to prevent a train from straddling the isolated section and causing it to go live. For example, a recent incident between London Road (Brighton) and Moulsecoomb resulted in the traction current being isolated back to Preston Park.

 

[Jonny]

Another downside is if an incident arises in the extreme but possible situation where passengers need to evacuate quickly off the train altogether in 3rd rail land.
--- old post above --- --- new post below ---

I would have thought that's more down to the nature of the route. The SE of England (where 3rd rail is) has some of the busiest services, often with many stops.

Possibly, but in my very limited experience of 3rd rail it is a bit on the slow side even when not stopping at every station.

 

[W230]

One downside of the third rail is when the emergency services go on the track, due to an incident, and the traction current is discharged over a large area, due to having abutting sections, to prevent a train from straddling the isolated section and causing it to go live. For example, a recent incident between London Road (Brighton) and Moulsecoomb resulted in the traction current being isolated back to Preston Park.

3rd rail sections are generally a lot shorter than OHLE sections. When the wires came down on the MML at Hendon last year there were plenty of trains stranded!

Jonny Another downside is if an incident arises in the extreme but possible situation where passengers need to evacuate quickly off the train altogether in 3rd rail land.

This doesn't happen very often though and an isolation can still be organised very quickly through the ECO or crudely with a short circuit bar.

Don't get me wrong - OHLE is better but the "safety case" for replacing it in this thread is more than a little far fetched! It's been with us a long time and there is good reason for that!

 

[Chris125]

My limited experience of 3rd rail is painfully slow trains. Is that due to the traction or something else?

Modern EMUs operate at reduced power on the 3rd rail due to the limited power supply available - hence the performance benefits of converting to OHLE.

Not if the words 'replaced with' used in the HLOS take their normal meaning.

It is generally assumed there'll be a period during the project when both systems will be live, but the DC won't be retained long term.

From the comments I've seen by those familiar with other sections of dual AC and DC operation it is not practical over long distances, and in any case the conversion is proposed when the existing equipment is due for renewal.

Chris

 

[LBSCR Times]

3rd rail sections are generally a lot shorter than OHLE sections. When the wires came down on the MML at Hendon last year there were plenty of trains stranded!l:

They might be shorter, but in circumstances such as a fatality, then how often is the OHLE isolated compared to the 3rd rail.

 

[HSTEd]

I am sure you would get better 'life saving' returns from putting this vast pot of money into eliminating level crossings.

Or better yet into more trains on more routes to reduce car journeys and thus get reduced road fatalities.

 

[Gareth]

Also, no one's ever been electrocuted by an unelectrified line, so perhaps decommissioning all electrified routes, third rail and OHLE, would be even better.

 

[NSEFAN]

Also, no one's ever been electrocuted by an unelectrified line, so perhaps decommissioning all electrified routes, third rail and OHLE, would be even better.

Maybe go back to mechanical signalling too, so nobody working on the S&T accidentally fries themselves either.

 

[yorksrob]

Maybe go back to mechanical signalling too, so nobody working on the S&T accidentally fries themselves either.

Although I did read about a signalman at Frant in Sussex being impaled on his mechanical relay equipment [V Mitchell & K Smith, Tonbridge to Hastings].

 

[Clip]

Also, no one's ever been electrocuted by an unelectrified line, so perhaps decommissioning all electrified routes, third rail and OHLE, would be even better.

Or just move the rail from ground level and put it directly above the middle of the train on top!!

 

[joeykins82]

The biggest case for converting 750V DC 3rd rail to 25kV AC OHLE is the energy cost and the acceleration improvements on stopping services; the safety improvements for both public and the workforce are obviously a plus but if it happens it'll be the 20% reduction in energy costs and the ability to run faster accelerating & higher speed services on the heavily congested routes south of London that gets it the approval

http://www.rssb.co.uk/library/research-development-and-innovation/research-brief-T950.pdf

 

[Yabbadabba]

One downside of the third rail is when the emergency services go on the track, due to an incident, and the traction current is discharged over a large area, due to having abutting sections, to prevent a train from straddling the isolated section and causing it to go live. For example, a recent incident between London Road (Brighton) and Moulsecoomb resulted in the traction current being isolated back to Preston Park.

After the initial emergency switch off with it's abutting sections you will often find that the area that is isolated will get reduced in size once the RIO is on scene and has taken over then emergency switch off. Quite often the abutting sections get recharged just leaving the area where the incident is taking place only isolated. Planed temporary switch offs will cover a short as possible section of railway as they can. While emergency switch offs by there very nature tend to edge on the side of caution to prevent trains livening up the electrical sections as they coast or brake to a stop as they pass into the effected area, that is after all what the abutting sections are for.

 

[edwin_m]

If ordinary OHLE is erected over live 3rd rail would the special dual voltage type of OHLE be required as long as when one was the other wasn't or would the whole section be required to be seen as dual voltage?

As far as I'm aware this is all to do with earthing. The rails are earthed on 25kV OLE and not on 750V third rail. So the OLE could be constructed while the third rail was still operating, then the system could be changed over in a weekend with earths altered at the same time (might need a few insulated rail joints installing too). After that all the dual-voltage trains would change system in a different place and work would start on the next section.

 

[Yabbadabba]

I had been wondering, before the unfortunate death at the depot this week, what the arrangements at the new Thameslink depot at Three Bridges will be?

I presume only Thameslink dual voltage stock will be maintained there, so is it planned for the depot to be electrified at 25Kv overhead rather than third rail?

Obviously, AC electrification has its own dangers; but at least it's not down on the ground in the same place as the depot's staff.

Well they are not adding AC regs to our rules as far as I know, so we are presuming it going to be DC throughout but with AC test pen like Selhurst and New Cross depots have.

 

[apk55]

The highest power our third rail system can supply is 4-5MW and this is at the expense of having a sub station every 1 to 2 miles and this has only been done in limited parts of the network typicaly where the eurostar ran. Most other parts of the network the power is limited to just over 2 MW with substation distance typicaly 3 miles. Even then the voltage drop mid section for a train drawing maximum current can exceed 100v, a considerable loss of energy heating the conductors.

In contrast our existing AC system can easily supply train loads of 10MW or more and this is with a substation distance of up to 20 miles or more for light traffic lines. For a light traffic branches it is posible that parts could be up to 15 or more miles from a substation, for example the Windmere branch could be supplied from the west coast line. As the distance between substations is quite large they are often located near where there is a convient bulk grid supply rather than the maximum distance. For DC systems feeders must be run to a bulk supply point which normaly means running cables alongside the track, looped into each substation. On parts of the network these cables are running at their limit and would need replacing for any upgrading.

 

[L&Y Robert]

Everyone is saying OHL is safer, better technically, more juice conveyed more economically to the point of consumption - i.e. the train, BUT Isn't it a visual mess! All those masts, gantries, wires and wot-not, especially at the feeder points and section gaps. One unsung benefit of third rail is that it is visually unobtrusive. Didya thinka that?

 

[jopsuk]

It's only really an "eyesore" in complex multi-track areas, that aren't generally the prettiest stretches of railway anyway often with many overhead signalling gantries. On standard sections of railway, it can be quite elegant if some effort is made

 

[snowball]

OHLE often looks ugly in railway enthusiast photographs which look along the track and are often taken with telephoto lenses. In a typical real-life view you see the railway from the side and only see one or two supports. The wires away from the supports are barely noticeable.

 

[jopsuk]

And in terms of priorities, enthusiast photos are really the lowest possible priority for an operational railway!

 

[anme]

And in terms of priorities, enthusiast photos are really the lowest possible priority for an operational railway!

Absolutely! Personally I quite like it - I find it rather elegant in most places.

 

[GRALISTAIR]

OHLE often looks ugly in railway enthusiast photographs which look along the track and are often taken with telephoto lenses. In a typical real-life view you see the railway from the side and only see one or two supports. The wires away from the supports are barely noticeable.

Ahhrr didums :roll:

And in terms of priorities, enthusiast photos are really the lowest possible priority for an operational railway!

ABSO - LUTELY - nearly as low as MOSI objections to the Orsdall curve. FUTURE, FUTURE, FUTURE

Absolutely! Personally I quite like it - I find it rather elegant in most places.

+1

 

[455driver]

Has Katada actually posted any suggestions or is this just another pointless thread started by somebody who has made nothing more than a statement about their personal opinion!

 

[GRALISTAIR]

Everyone is saying OHL is safer, ---- BUT Isn't it a visual mess! All those masts, gantries, wires and wot-not, especially at the feeder points and section gaps. One unsung benefit of third rail is that it is visually unobtrusive. Didya thinka that?

I think it is Switzerland that has 100% OHLE and I also think most people would say Switzerland is one of the most beautiful countries on earth. IIRC

 

[Gareth]

I don't find much of the modern overhead wiring that bad. Same with tram catenary, if you compare modern systems like Metrolink with the older tram systems that were decommissioned 50+ years ago.

 

[Julian Hornby]

There are many deaths on the railway like level crossing fatality's or passengers being struck by trains. More people die from level crossings and foot crossings so why shouldn't we spend the money on removing them instead of changing the third rail. Most people who are on the track are trying to commit suicide, being stupid or doing work. Not many people die from the third rail every year, therefore I don't think it's a good idea to spend so much money converting it to overhead wires. Also, if line restriction is 100 or below and it's electric trains running what's the point of paying for expensive overhead wires?
Another thing, where's the money?


Julian.

 

[L&Y Robert]

I don't find much of the modern overhead wiring that bad.

Bad, though! Just not that bad. Well, it takes all sorts - some people like pylons I believe. And telegraph poles! (There's a thread on here somewhere). And cars, even.

 

[Taunton]

I never encountered a third rail electrocution fatality.

I did however encounter a couple of separate 25 Kv incidents to teenagers, one climbing onto the roof of vehicles in a siding, the other throwing wire from an overbridge. You are not incident-free with it.

 

[edwin_m]

Also, if line restriction is 100 or below and it's electric trains running what's the point of paying for expensive overhead wires?
Another thing, where's the money?

As posted up-thread by various people:

- Better acceleration at all speeds
- 20%-ish saving on the energy bill should pay for the capital cost over time
- A lot of the third rail equipment is due for replacement anyway, so replacing by OLE may not cost much more than replacing like-for-like

Obviously rather theoretical at present but this is what is claimed.

 

[59CosG95]

I think that replacing the existing network of 3rd rail (bar Merseyrail deep-level, as the tunnels will be nigh on impossible to electrify for any forseeable benefit) should be a priority, as further wiring of the network is due to take place in the near future. If we have a theoretically fully electrified network (with Southern Region on DC), the costs will be astronomical. All OHLE-slightly less astronomical. Besides, what's the point of all this expensive dual-voltage stock (375s, 376s, 450s, 458s, 444s) if we don't allow them to make use of their capabilities?

Speaking from regular SWT travel, I'm very sure that 110mph running could be achieved with the 450s and 444s if the network was wired around the mainline. There are plenty of straight sections, so should be relatively easy to reach 110. And Southeastern's 375/6 fleet has pantographs they never even USE. We should definitely give them somewhere to run under the wires.