Abandonment of Third Rail. Up for discussion.

[Titan]

Unfortunately Network Rail neither designs or builds them, and has a habit of committing itself to projects that there are insufficient resources in the country to complete. Not only that, but even if it was possible to expand the resources as quickly as required - you would end up with a large number of inexperienced people, which results in many mistakes!

[Ian J.]

Surely retraining of staff and building up sufficient practical resources for the Southern area to look after itself would not be out of the question? This is, after all, a 30-50 year timespan we're talking about, so a dedicated team made up of ex-third rail staff would be sensible?

[Edwin_m]

Sometime since I last looked, a "Summary Report" has appeared on the RSSB website. I'm not qualified to comment on the cost rates used, but it does appear to have allowed for the costs of structure replacement, signal immunisation, rolling stock conversion etc. It also takes a prudent view of benefits, not claiming any where there is any doubt, and seems generally sound apart from a few trivial errors (such as believing electrification extends to Leamington today!). It even mentions the effect of resources in limiting the rate of conversion. The benefit-to-cost ratios are not brilliant, which suggests that money should perhaps be spent on something else instead like electrifying some non-electric routes, but more detailed work might improve the BCR by taking out some of the pessimism.

[TheSignalEngineer]

.......... apart from a few trivial errors (such as believing electrification extends to Leamington today!).

Signals at Gibbet Hill, between Coventry and Leamington, were prepared for electrification in the early 1960s. The original WCML propoals included wiring Rugby - Leamington - Coventry - Nuneaton, but this was dropped due to budget cuts along with Stafford PSB.

[Ian J.]

The report mentions the Bournemouth - Waterloo line as an 'exemplar' case, and includes a reference to gap-filling from Oxford to Leamington.

[Xerces Fobe2]

Politicians will have to make the decision so don't expect this to happen for at least another couple of decades!

 

XF

[The Stationmaster]

The fact that this emanates from RSSB leaves me wondering if they are just looking for a role in life. I have heard that their are already whisperings, if not actual proposals, within NR to takeover RSSB's safety role and while that causes me a few misgivings it would at least reunite power (of setting standards) with responsibility (for maintaining those standards - albeit not all of it but definitely far more responsibility than RSSB currently has).

 

I've no doubt that 'someone' needs to think strategically for the industry and while I don't necessarily know the best place for that to be done I certainly don't put RSSB anywhere near that category if some of its publications which are meant to create operational safety are any guide (I am still pondering how to amend the Rule Book using the amendments which they issue, and I'm not the only one).

[Suzie]

From what I can recall of that conversion from 'outside the fence' it involved little or no work on structures, and no changes to the ohle itself (although obviously the feeder arrangements had to change) but of course there was signalling immunisation and bonding etc work required. I seem to recall that the actual changeover was done over a weekend, or part thereof, with no more than a day or so's suspension of service.

 

Now contrast that with the possessions required to alter a single overbridge to either 25kv ohle or the largest container loading gauge - a minimum of two weekends of lines closed one of which will be either a 48 hr or 72hr possession. The last single span over quadruple track renewal which I watched included a 50+hr possession purely to take out the old and put in the new, arch bridges of course take longer. And of course signalling changeover possessions in any halfway reasonably sized interlockings are now measured in days (although I grant that might be happening anyway as equipment is modernised).

 

Thus I somehow find it difficult to rationalise the proposition that converting from 3rd rail to ohle is 'easier' that doing litte more than changing the supply voltage and frequency in existing ohle.

 

The railway being closed on Saturday and Sunday (replaced with buses) is a perfectly normal experience for some of us, When going from 3rd rail to overhead there is the advantage of being able to use dual voltage trains while the infrastructure is gradually improved, and the two systems can be made to work together so there is no need for a big-bang changeover where all trains have to be withdrawn on a Friday and replaced with new on the Monday.

[31A]

Sometime since I last looked, a "Summary Report" has appeared on the RSSB website. I'm not qualified to comment on the cost rates used, but it does appear to have allowed for the costs of structure replacement, signal immunisation, rolling stock conversion etc. It also takes a prudent view of benefits, not claiming any where there is any doubt, and seems generally sound apart from a few trivial errors (such as believing electrification extends to Leamington today!). It even mentions the effect of resources in limiting the rate of conversion. The benefit-to-cost ratios are not brilliant, which suggests that money should perhaps be spent on something else instead like electrifying some non-electric routes, but more detailed work might improve the BCR by taking out some of the pessimism.

 

Perhaps someone said 'Lymington'?!

[Southernman46]

Signals at Gibbet Hill, between Coventry and Leamington, were prepared for electrification in the early 1960s. The original WCML propoals included wiring Rugby - Leamington - Coventry - Nuneaton, but this was dropped due to budget cuts along with Stafford PSB.

 

Aye - many of the bridges on the GW mainline / Berks & Hants were raised for electrification in the early 70's - nothing like a bit of forward planning

[The Stationmaster]

Having just had a read through it I find some parts a bit odd. The weirdest is the suggestion that there should be mininmal clearance problems where the LBSCR ohle was in use - very strange considering that it worked to much tighter electrical clearances than have ever been used for 25kv ohle in Britain (6.25 kv might be ok?) and it assumes that structures haven't changed in getting on for 100 years - I wonder.

 

The other thing I find very odd is the need to include and discuss 1500 and 3000 volt ohle systems - technically outmoded by the 1950s and why mention 1500vdc overhead in Switzerland - where I understand it is only used by 3 narrow gauge lines - instead of, say, Holland where it is the national system?!

[Edwin_m]

I guess the remit for the work asked them to consider all the options, and they did rule out 1500V and 3000V pretty quickly. There was a photo of 1500V overhead in the Netherlands, as well as some mention of possible conversions to 25kV there, so they were obviously aware of that.

 

Elsewhere in the report there is a table of clearances for the different voltages, which makes the point that those for 25kV are only slightly more than those for 1500V or 3000V (minimum clearances were much more in the early days of 25kV, hence the 6.25kV used in urban areas, but they were reduced later). This suggests that the clearances for 6.6kV might also allow for 25kV, though for a system that disappeared the best part of a century ago there must be some doubt about whether those clearances still exit.

[The Stationmaster]

According to Stephen Grant's illustrated album on the LBSC electrification the standard minimum clearance was 10 inches made up of 4 ins between the top of the loading gauge and the contact wire, 2 ins for flexing of the catenary and 4 ins from catenary to structure. However in places - which seem mainly to have been bridges which weren't altered the live wire - structure clearance was reduced to 2 inches by using a rigid bar instead of normal contact wire Reportedly very few bridges were rebuilt to accommodate the electrification.

 

Special arrangements were used at Victoria because of the two low bridges on the approach (Ebury Bridge and Elizabeth Bridge) plus Eccleston Bridge which effectively meant minimal clearance - whether these bridges have since been raised, or tracks lowered, could be an interesting issue.

[Ian J.]

Paragraph 37 of the 'Railways Act 2005 Statement' (released today, 16th July, 2012):

 

37. The southern end of the Electric Spine entails the conversion of a section of the existing Southern ‘third rail’ (750V DC) electrification system to the more modern and capable ‘overhead’ (25kV AC) system to upgrade its capability. The Secretary of State also wishes the industry to develop a longer-term proposition and business case for the systematic upgrade from DC to AC of the whole Southern network, for consideration for future control periods. As part of this work the industry will wish to treat the conversion work required for Southampton to Basingstoke as a pilot scheme for such a potential modernisation programme, and review plans for renewing or upgrading the DC network to avoid the risk of nugatory expenditure.

 

So it looks to be a conversion from third rail to overhead, not an installation of overhead alongside third rail. It will definitely mean conversions of the existing fleet to dual system third rail/overhead.

[The Stationmaster]

Paragraph 37 of the 'Railways Act 2005 Statement' (released today, 16th July, 2012):

 

 

 

So it looks to be a conversion from third rail to overhead, not an installation of overhead alongside third rail. It will definitely mean conversions of the existing fleet to dual system third rail/overhead.

So it's going to be very interesting to see how passenger trains from the London end will be dealt with at Basingstoke & sou' west thereof - lots of dual system conversion work on the horizon for Siemens perhaps?

[Karhedron]

So it's going to be very interesting to see how passenger trains from the London end will be dealt with at Basingstoke & sou' west thereof - lots of dual system conversion work on the horizon for Siemens perhaps?

Should not be too hard. The Desiros have pantograph wells already. The 450s are basically a DC-only version of the 350s. I live in Basingstoke so the prospect of seeing the switchover there is interesting.

[ChrisH]

Oh goody, our services are going to be a pilot scheme. That fills me with confidence.

 

But seriously, the Desiros should be a fairly easy convertion, All the 444s would need doing, but the service would only require a limited number of 450s except for one problem, remember the maintenence facilities are at Northam.

 

The Southern are going to be impressed as well having to supply dual voltage sets for Brighton Southampton services just for the last couple of miles.

 

Chris

[Ron Ron Ron]

The Desiro's don't just have benefit of panto wells.

Apart from being dual voltage ready, they're designed with most of their equipment in modular form. The primary benefit being easy maintenance, where equipment modules can be easily removed for maintenance or replaced.

 

From what I understand, the conversion between AC and DC is straightforward.

Other than shoe beams and pantographs, I'm not sure if it involves adding and removing any modules and reconfiguring of the systems, but in essence this is not a major re-engineering job and is relatively easy to carry out.

 

There are a lot of 450 movements south of Basingstoke, in addition to the 444 express services and as pointed out the Siemens depot is located at Northam in Southampton.

A conversion program to dual voltage would naturally involve the whole Desiro fleet.

[Karhedron]

The Southern are going to be impressed as well having to supply dual voltage sets for Brighton Southampton services just for the last couple of miles.

My guess is that the last few miles would probably retain 3rd rail for the benefit of such services. The 3rd rail would probably only be removed between Basingstoke and Eastleigh for the pilot.

[Glorious NSE]

Yes I would have thought that it would need to be 'dual' from St Denys at the absolute minimum, and Eastleigh is probably logical.

[John M Upton]

It would have to continue up to Eastleigh, some of out Brighton - Southamptons run via Eastleigh to serve the airport (and provide certain members of train crew with a regular fix of locos and grotty wagons...)

[Edwin_m]

Surely the Southern units that run that far west are either 375s (dual voltage already or easily convertible) or 313s (formerly dual voltage but with pans removed I think).

[chrisf]

Here is a chance to point out my complete ignorance, folks, for this is a serious question. Can someone explain what if anything would be the objection to installing 25kV AC and having it co-exist with 750v DC for as long as is necessary for DC stock to become life expired? It co-exists for short lengths at changeover locations such as Farringdon and Acton Central but what would be the practical problems of having both systems for a significant distance?

 

Chris

[Edwin_m]

There's no particular problem with fitting both systems, and no doubt any conversion programme would include some sections of dual fitment. However the case for converting to OLE partly relies on avoiding the cost of renewing the third rail equipment, so it wouldn't be worth doing if the third rail was kept.

[Glorious NSE]

Surely the Southern units that run that far west are either 375s (dual voltage already or easily convertible) or 313s (formerly dual voltage but with pans removed I think).

 

Yes, but is it worth having to convert the (DC) 375s to cover just a few miles of track...if the pilot were to become a rolling programme then eventually they would be, but is having the cost of that against this project a good move?

 

(Although having said that it also talks about Southern WLL services becoming 8 cars, which would probably require more dual voltage 375s anyhow)

 

The station area's at Southampton, Eastleigh and St Denys would (at least partially) have to retain 3rd rail anyhow to allow trains to arrive and change over...