Pros and cons of different electrification schemes (e.g. 3rd rail / OHLE / battery power)

[hwl]

That makes sense, and having done a fair bit of walking around on 4th rail electrified track I can vouch for it. You really have to think hard when you step through pointwork.

Therefore I would suggest that 3rd rail electrification of lines such as the North Downs and the Uckfield branch would come with a risk no-where near as great as the claimed average figure of 10x that of OHL. Because in those cases the electrification would mostly be on plain line. Guildford, Shalford Junction, the Reigate-Redhill area, and Hurst Green, the junction areas, are already 3rd-rail electrified. Moreover, the trains to operate those lines would use, I'm sure, existing electric depots, so no added risk there.

There is also the fact that the present unelectrified parts of the North Downs line and the Uckfield branch go through some thinly populated areas - it is quite a long country walk even to reach most parts of the North Downs line.

The 8.something (from memory) difference includes passengers running after their dog from Waterloo - Queenstown Road...

 

[A0wen]

Poor fencing is one of the main trespass risk drivers for 3rd rail risk

I don't disagree. But 3rd rail wasn't the problem on those cases.

I'm no fan of 3rd rail - leaving an exposed HV supply at ground level is a risk for anyone there - and that includes people who should be there. Extending it isn't desirable except in areas where OHLE really isn't practical e.g. sub-surface such as Merseyrail tunnels. I'd like to see battery units in use with short sections of 3rd rail to allow charging.

 

[AM9]

That makes sense, and having done a fair bit of walking around on 4th rail electrified track I can vouch for it. You really have to think hard when you step through pointwork.

Just because the hazard of junctions isn't as present which I would guess is where the incidents normally involve track workers, that doesn't mean that the risk of trespass isn't there.

Because it was cited in this thread which was about extension of 3rd rail. Yet the injuries sustained weren't a consequence of the 3rd rail on these occasions.

I mentioned it as an example of a failure to prevent access to a hazard. The fact that in that particular case it was an OLE hazard doesn't alter the fence owner's culpability. I entered that from memory, - had I recalled a case of a fence protecting trespassers from 3rd rail hazards, the actual hazard would have been just as irrelevant to the argument, - it is the additional burden of miles of secure fence that is the cost.

 

[Bletchleyite]

If you shielded all of the third rail there would be nowhere to short circuit it, though. You'd only ever want to do it in emergency, in a normal evacuation you'd get the power turned off, it's a pretty extreme way of blowing the power. You basically short from the third rail to the running rail, but not where the running rail is the track circuit as it'll just likely blow up the signalling.

Presumably a different style of short circuiting device could be designed that would short from the top of the third rail to the running rail? Or gaps could be left for that purpose?

 

[Railcar]

Third rail doesn't disfigure the countryside.

While OHLE 'knitting' is acceptable in an industrial landscape, in the countryside it can be visible over a wide area. In contrast, a simple railway track (whether two or three rails) can 'melt' into the scenery.

Yes, safety and grid electricity supply and all the other factors already mentioned are important, but in this fairly small island, uncluttered views across the countryside have a value in human terms.

 

[HSTEd]

Presumably a different style of short circuiting device could be designed that would short from the top of the third rail to the running rail? Or gaps could be left for that purpose?

I begin to question whether a local short circuiting bar is actually that useful in the GSM-R era.
Just give traincrew handheld GSM-R radios.

 

[Bletchleyite]

Third rail doesn't disfigure the countryside.

While OHLE 'knitting' is acceptable in an industrial landscape, in the countryside it can be visible over a wide area. In contrast, a simple railway track (whether two or three rails) can 'melt' into the scenery.

Yes, safety and grid electricity supply and all the other factors already mentioned are important, but in this fairly small island, uncluttered views across the countryside have a value in human terms.

Is this really that much of an issue? The WCML fits nicely over Shap or through the Chilterns, it's the roads there that blot on the landscape.

 

[AM9]

Is this really that much of an issue? The WCML fits nicely over Shap or through the Chilterns, it's the roads there that blot on the landscape.

There really are some bizarre justifications for an antiquainted inefficient rail power system here.

 

[GRALISTAIR]

Is this really that much of an issue? The WCML fits nicely over Shap or through the Chilterns, it's the roads there that blot on the landscape.

You only need to look at side by side in the Lune Gorge. You barely notice the railway in that magnificent location. The M6 motorway on the other hand is an eyesore.

 

[hwl]

As a thought on de-risking:

Traditional platform end ramps have much higher trespass issues than the current sheer drop / railing / gate/ steps approach for new build or modified platforms ends...

Most 3rd rail area platforms still have ramps (and more certainly did when the previous risk work was done, the SW and SN 10 car metro and Uckfield line platform lengthenings will have reduced the number in the interim)

 

[Dunfanaghy Rd]

Third rail doesn't disfigure the countryside.

While OHLE 'knitting' is acceptable in an industrial landscape, in the countryside it can be visible over a wide area. In contrast, a simple railway track (whether two or three rails) can 'melt' into the scenery.

Yes, safety and grid electricity supply and all the other factors already mentioned are important, but in this fairly small island, uncluttered views across the countryside have a value in human terms.

As someone who once worked around the 3rd rail, and has the scars to show for it, I marvel at how often people defend it in comparison to OLE.
Pat

 

[urbophile]

Is this really that much of an issue? The WCML fits nicely over Shap or through the Chilterns, it's the roads there that blot on the landscape.

Switzerland is noted both for scenic beauty and the almost entirely electrified (overhead) rail network. Has anyone suggested any incompatibility between them?

 

[si404]

The WCML fits nicely over Shap or through the Chilterns, it's the roads there that blot on the landscape.

Yes the roads are horrible scars, but the railways are too. They're just older scars and have healed more. The WCML carves through the Chilterns with a cutting nearly as big in volume as the rather infamous M40 cutting, but because it's nearly 200 years old, it just feels part of the landscape, unlike the 50 year old motorway. It's matured, and hidden by foliage (including when in it), so you just don't notice it so much.

I would say it's not the wires, but the earthworks. However, Chilterns AONB campaigned for an improvement in the GWML electrification plans due to the masts being unsightly: 'Save the Gap', and were successful in getting money for enhance the area (I'd imagine more, and taller, tree screening of the railway) affected: 'Mend the Gap'. They thought it was a problem, and Network Rail agreed.

You only need to look at side by side in the Lune Gorge. You barely notice the railway in that magnificent location. The M6 motorway on the other hand is an eyesore.

An eyesore that won a prize for improving the landscape. There's a plaque saying: "This award for an outstanding contribution to the appearance of the Westmorland landscape relates to the 36 miles of M6 Motorway between the Lancaster and Penrith by-passes".

They did put a lot of effort to minimise the negative effects of the road - especially for the 60s. The railway is only 'better' as it's half the width and the mitigation is more mature. It's as much of a scar across the landscape as a carriageway of the motorway.

----

Though the bigger problem of blight is not the effect on the landscape, but noise - and electric railways are better for that than unelectrified railways. And roads are terrible.

 

[Taunton]

It is not feasible to summarise this but I note a statement that the risk of electrocution with third rail is ten times higher than for overhead

Is this based on a theoretical calculation or actual numbers? Because I have noted several events reported in recent years on 25Kv (broken wires; trespassers on stock roofs in sidings; items thrown over overbridges, etc), and if 3rd rail is experiencing 10 times that number I'm sure we would be hearing about it.

 

[O L Leigh]

Is this based on a theoretical calculation or actual numbers? Because I have noted several events reported in recent years on 25Kv (broken wires; trespassers on stock roofs in sidings; items thrown over overbridges, etc), and if 3rd rail is experiencing 10 times that number I'm sure we would be hearing about it.

You may be surprised to learn that it is the media and not the railways that decide what is or is not newsworthy.

However, if you had chosen to spend a few minutes working your way through the various links, as I have done, you would have found yourself reading the ORR DC Electrification Policy Statement which, as the title suggests, sets out their position as the regulator. In it they state the following:

ORR’s most significant concern in regard to legacy third rail systems (the “legacy network”) is the running of bare, live conductors through publicly accessible areas. These conductors are not insulated or shrouded. The legacy network does not allow quick, secure isolations, and exposes individuals to a range of risks whilst carrying out isolations. Due to the difficulty in obtaining isolations on the legacy network, a lot of work tends to be carried out on or near the live conductor, further undermining safety and weakening compliance with the applicable legislation. This is not an abstract or theoretical risk: the harm done to both workers and members of the public by the legacy network occurs significantly more frequently than on the overhead AC network.

There is then a reference to a footnote which reads:

This is borne out by data from RSSB’s safety risk model – despite the legacy network being only half the size of the AC network (4400km compared to 8200km), it contributes almost eight times more (in terms of fatalities and weighted injuries per year) to overall risks on the railway. See FWI comparative data for OLE / conductor rail / non-electrified: Network Rail Electrical Power Asset Policy December 2012 (Table 2.1, page 52).

 

[HSTEd]

Not allowing fast isolations is hardly an inherent problem with third rail though.

 

[O L Leigh]

Not allowing fast isolations is hardly an inherent problem with third rail though.

Perhaps not. But it is particularly a risk where it is associated with CRE due to it's location on the ground. No particular care needs to be exercised when, say, lifting and packing under the OLE (except perhaps vigilance for detached red bonds), but it does where there is CRE.

 

[Mikey C]

There is then a reference to a footnote which reads:

But then a higher proportion of OHLE installations are across open countryside where there is far less risk of human contact. The vast network of 3rd rail lines that cover south London are far closer to large areas of the population than say the ECML which adds massively to the OHLE mileage, but mainly avoids urban areas.

Yes I accept 3rd rail is more dangerous than OHLE and sub-optimal in many ways, but an alternative way of looking at it is that we accept roads going through town with no barriers to stop someone walking in front of a speeding road traffic. All things are relative, seeing that 400 pedestrians die every year on the roads...

 

[philthetube]

The enthusiasm for 3rd rail extensions being bolstered here by various mitigation of the considerable health and safety issues seems to befogetting one major cost driver: that of inspection and maintenance. Areas that spring to mind include:

The additional cost of debris, leaves and occasionally snow and ice on any live 3rd rail shielding hardware​

The requirement to ensure the integrity of fences and barriers designed to prevent trespasser access to the live track, - note that the railway has been severely punished for failing to secure damaged fencing around sidings when a child trespassing received life-changing injuries following an electric shock.​

The maintenance of ever more complex signalling and power supply integration through EMC issues​

So labour and material costs associated with those are added to the perennial big number extra costs, e.g. higher power distribution costs, greater power losses, reduced performance of traction and the ever present climatic interruptions of snow and ice.
The other consideration is that those costs are perennial so for an expected life of 50 years, the 3rd rail solution has all of those addirtional running costs. The higher costs that might occur when 25kV schemes are implemented is a once-off cost, so the balance might be considerably different if all of the true costs are included, rather than just thinking about the high cost of replacing a few low bridges a bit earlier than might have been necessary otherwise.

I don't think the debris issue is as much of a problem as is suffered by ole, most debris issues are caused by the track being obstructed not the power supply, additionally repairs following damage are normally much quicker and easier to facilitate.

Smow an Ice can be mitigated against buy having heated rails, similar to heated points, it is done in some vulnerable areas now,

 

[O L Leigh]

But then a higher proportion of OHLE installations are across open countryside where there is far less risk of human contact. The vast network of 3rd rail lines that cover south London are far closer to large areas of the population than say the ECML which adds massively to the OHLE mileage, but mainly avoids urban areas.

I had a feeling this would be raised. The point of posting the information was so that @Taunton could be confident that the figures were real and not simply madey-uppy ones.

But I don't think that this factor is sufficient to explain the disparity alone. If a network half the size has eight times the risk, then aren't we talking about CRE imposing something like 16 times more risk per mile than OLE...?

Yes I accept 3rd rail is more dangerous than OHLE and sub-optimal in many ways, but an alternative way of looking at it is that we accept roads going through town with no barriers to stop someone walking in front of a speeding road traffic. All things are relative, seeing that 400 pedestrians die every year on the roads...

I'm afraid that it doesn't exactly wash. There are regulations in force now that preclude the use of CRE that were not in existence at the time the legacy network was electrified. This doesn't mean that the industry can simply ignore them on the basis that it was OK back in the 40s. Also, comparisons between road and rail are not always helpful or even pertinent, and I fear that this one falls into that category.

I don't think the debris issue is as much of a problem as is suffered by ole, most debris issues are caused by the track being obstructed not the power supply, additionally repairs following damage are normally much quicker and easier to facilitate.

Smow an Ice can be mitigated against buy having heated rails, similar to heated points, it is done in some vulnerable areas now,

I'm not sure that is the point being raised. I think the issue with debris is that when it needs to be removed from the line the CRE is a hazard to staff undertaking this task where it is not necessarily so with OLE, rather than debris specifically affecting whichever electrification system.

 

[HSTEd]

I'm afraid that it doesn't exactly wash. There are regulations in force now that preclude the use of CRE that were not in existence at the time the legacy network was electrified. This doesn't mean that the industry can simply ignore them on the basis that it was OK back in the 40s. Also, comparisons between road and rail are not always helpful or even pertinent, and I fear that this one falls into that category.

And yet third rail electrification projects continued after the Electricity at Work regulations were promulgated and noone questioned it.
This is a later view, held by the ORR, that is not directly supported by legislation or case law.

 

[delticdave]

One way to reduce the safety risk of 750V DC top contact 3rd rail would be to copy the installation at the Siemens test track at Wildenrath (Germany). The 3rd rail appears to have been totally clad in insulation material, except for the top of the rail.

Just a thought.......

 

[Roast Veg]

Do you have any pictures of that installation?

 

[MadMac]

One way to reduce the safety risk of 750V DC top contact 3rd rail would be to copy the installation at the Siemens test track at Wildenrath (Germany). The 3rd rail appears to have been totally clad in insulation material, except for the top of the rail.

Just a thought.......

LA Metro Red Line Yard - that's a fibre glass cover on top. It's like that throughout the subway system.

 

[Roast Veg]

That is not possible with the current position of the 3rd rail in the Southern Region - directly under the bogies.

 

[HSTEd]

Do you have any pictures of that installation?

Credit to one Wolfgang Scheer and "Railcolor News"

The rail certainly looks peculiar
If you look at the rail on the curve its not a simple kickboard either.

 

[Roast Veg]

I like how every second red marker has a "do not touch" warning! It appears the insulation is only applied on the outermost edge.

 

[Bald Rick]

And yet third rail electrification projects continued after the Electricity at Work regulations were promulgated and noone questioned it.
This is a later view, held by the ORR, that is not directly supported by legislation or case law.

I thinks it’s reasonable to suggest that the ORR have developed their view following years of case law following the EaW regulations, and the rail industry not being minded to help much.

Any new electrification will be subject to the requirements of ROGS and, in particular, The Common Safety Method (CSM) for risk assessment. It is this, and this alone - because it will be site specific - that will be the deciding factor within British Law.

Is, of course, the correct answer.

 

[HSTEd]

I like how every second red marker has a "do not touch" warning! It appears the insulation is only applied on the outermost edge.

I suppose you'd have to conduct trials.

Perhaps by getting two similar mocked up track sections, putting volunteers in coveralls, covering the conductive parts of the rail in paint and then asking people to cross over and over.
Then determine if the rail desgin reduces the amount of paint transfer.

 

[Horizon22]

Is this really that much of an issue? The WCML fits nicely over Shap or through the Chilterns, it's the roads there that blot on the landscape.

Bath weren't particularly keen on it, although that's partly to do with the viaduct as well.