Great Western Main Line electrification - ongoing discussion

[whole diary]

[TaplowGreen]

I see it runs to 144 pages, any chance of a summary of the most important points?

[Red Squirrel]

More waffle.

That's as as may be ..........

However politicians, policy influencers, DfT^» (Department for Transport - about) etc will use this report to support their particular objective regarding railway electrification for many years to come

...which, if I've read it right, is a bit depressing really.

[stuving]

I see it runs to 144 pages, any chance of a summary of the most important points?

Well, there's section 7.1 "summary". But it is worth showing the very first section:

1.1 Study profile

The DfT^» (Department for Transport - about) commissioned SYSTRA, and subconsultants Tavistock Institute of Human Relations (Tavistock Institute or TIHR), to undertake a first post-opening evaluation for key elements of the Great Western Route Modernisation (GWRM) and related investments, primarily in respect of the long-distance service provision.

The specific objective of the study is to provide an assessment of the benefits delivered by the GWRM programme to date, including a value-for-money assessment of the long-distance service components in the form of a post-opening cost-benefit analysis. The evaluation also considers how the scope of works has changed within the programme lifecycle, and the impact this has had upon the achievement of intended objectives.

7.1 Summary

This first post-opening evaluation indicates that the GWRM programme has broadly met the founding expectations with regard to delivering passenger benefits.

The programme was descoped to control costs, but with little impact on the overall passenger benefits. It has delivered expected capacity increases, journey time and frequency improvements and, although it is not quite at the target set, reliability has improved significantly and is above the level achieved by most other long-distance operators.

The descoping of the programme has resulted in a slight reduction of environmental benefits compared to founding expectations but has still substantially contributed to reducing GWR^▸ (Great Western Railway)’s environmental impact. The environmental benefits from the programme have not been eroded as much as might have been expected as much of the impact of the descoping has been offset by other decisions made, particularly to procure all bi-modal trains for the long-distance fleet.

At this early stage of evaluation, it is not possible to assess how the programme has contributed to wider social and economic vitality and regional development. However, the expansion in capacity and reduction in journey times already delivered by the programme would point towards the potential to meet these wider objectives in the longer term.

In the 2015 Business Case, driven by a monetised economic appraisal, the GWRM programme was initially expected to deliver a ’High Value for Money’ as categorised by the DfT in their Value for Money guidance. Following the cost increases observed in the early delivery stages, the updated appraisal of 2017 reassessed this allocation and suggested the programme would delivery ‘Low Value for Money’. The assessment in this evaluation suggests that while the long-distance components of the programme may be expected to generate a higher monetised benefit to cost ratio, the value for money allocation would remain as ‘Low’.

Of course some of that doesn't make much sense without reading other bits as well.

[stuving]

POPE (post-opening project evaluation) has been a routine part of how Highways England manages projects for 15 years. ORR^» (Office of Rail and Road formerly Office of Rail Regulation - about) even did a study of POPE studies. It's all part of "benefits management", a term I suspect we'll hear more of in railway projects. It ought not to make a lot of difference, though, since railway planners don't tend to lose sight of the benefits being asked for as much as some others.

[onthecushions]

What should have been included (if it's not) is a comparison of current costs (now we've spent time on the learning curve and don't drill through signalling cables etc) with current benefits.

Current costs are lower than those of the GWEP^▸ (Great Western Electrification Program) and more so if inflation is included.

The costs of the treasury/DfT^» (Department for Transport - about) de-skilling Railtrack/NR^» (Network Rail - home page) would therefore emerge.

The costs of not completing the peripherals (Oxford, Bristol) could also be evaluated

I imagine that's why MML^» (Midland Main Line. - about) and TP wiring is continuing.

OTC

[stuving]

The builders of the Holly Cross ATFS (at Bramley) have now put in their (auto)transformer, and have made a video of it. As they (Enable Infrastructure) say:

The video showcases the entire process at Holly Cross from a green, pastoral field to the initial foundation works to the arrival and installation of crucial technology such as Transformers, Structure Mounted Outdoor Switchgear (SMOS) pallets, and the Module building.

It shows how now not only does switchgear perch on top of poles, but the poles arrive factory-assembled on pallets (as does the control shed). Holly Cross ATFS sits partway along a feeder from the grid to the railway at Reading, which is the only place it's connected to the OLE^▸ (Overhead Line Equipment, more often "OHLE"). Since it's the same kind of circuit - 25-0-25 kV - all the way, you may wonder why you need all this stuff including the AT connected across it at that point.

[TonyK]

The builders of the Holly Cross ATFS (at Bramley) have now put in their (auto)transformer, and have made a video of it. As they (Enable Infrastructure) say:

The video showcases the entire process at Holly Cross from a green, pastoral field to the initial foundation works to the arrival and installation of crucial technology such as Transformers, Structure Mounted Outdoor Switchgear (SMOS) pallets, and the Module building.

It shows how now not only does switchgear perch on top of poles, but the poles arrive factory-assembled on pallets (as does the control shed). Holly Cross ATFS sits partway along a feeder from the grid to the railway at Reading, which is the only place it's connected to the OLE^▸ (Overhead Line Equipment, more often "OHLE"). Since it's the same kind of circuit - 25-0-25 kV - all the way, you may wonder why you need all this stuff including the AT connected across it at that point.

I certainly wonder. But GCE O-level Physics in 1972 only just equips me with enough knowledge to grasp the basic theory, even if I did get top grade. I believe it effectively doubles the voltage applied to the engine by using split phase power and using the return current from the rail, at not much extra cost, but I'm sure someone will do a far better job of covering the point than that.

[Electric train]

The builders of the Holly Cross ATFS (at Bramley) have now put in their (auto)transformer, and have made a video of it. As they (Enable Infrastructure) say:

The video showcases the entire process at Holly Cross from a green, pastoral field to the initial foundation works to the arrival and installation of crucial technology such as Transformers, Structure Mounted Outdoor Switchgear (SMOS) pallets, and the Module building.

It shows how now not only does switchgear perch on top of poles, but the poles arrive factory-assembled on pallets (as does the control shed). Holly Cross ATFS sits partway along a feeder from the grid to the railway at Reading, which is the only place it's connected to the OLE^▸ (Overhead Line Equipment, more often "OHLE"). Since it's the same kind of circuit - 25-0-25 kV - all the way, you may wonder why you need all this stuff including the AT connected across it at that point.

The switchgear is called SMOS lite (SMOS Structure Mounted Outdoor Switchgear) lite because the concept is lite in site construction and implementation compared to the 1990's SMOS.  The "control shed" or correctly the Ancillary Equipment Enclosure contains the Protection Relays, control and protection power supply battery chargers, SCADA^▸ (System Control And Data Acquisition,) etc. 

The 2 Auto-transformers at Holly Cross I am guessing is to ensure the Grid Transformer is presented with balance current on the 2 phases and not have any current on the Earthed Neutral.  The railways with its rail return on an AT system will present a Neutral current at the Grid transformer which cause circulating currents in the transformer and overheating.  The traction return current will find the shortest route back to the transformer and given the Berks and Hants is not that far away return current could find a fortuitous path

I certainly wonder. But GCE O-level Physics in 1972 only just equips me with enough knowledge to grasp the basic theory, even if I did get top grade. I believe it effectively doubles the voltage applied to the engine by using split phase power and using the return current from the rail, at not much extra cost, but I'm sure someone will do a far better job of covering the point than that.

The train is still powered at 25kV and not 50kV.  The power is distributed at 50kV one leg is the centenary the other is the Auto Transformer feeder wire, both are 25kV relative to Earth.  Distributing the power at 50kV reduces the I²R losses, the down side is every so often it needs a transformer and Auto Transformer which is a 25kV - 0 - 25kV transformer,
   

[Red Squirrel]

New plans to electrify train lines from Bristol Temple Meads to Parkway, Filton, Bath and Chippenham

Previous plans to upgrade railway tracks in the region were scrapped in 2016

New plans to electrify railway lines in the West Country, starting with tracks from Bristol Temple Meads station, have been announced by the region's metro mayor.

Under Dan Norris's scheme the lines from Temple Meads from the north via Bristol Parkway and Filton Bank will be electrified during the first phase, with the mayor then planning move on to the section of railway that runs from Bristol to Bath Spa and Chippenham in Wiltshire.

[...]

Mr Norris said on Thursday (February 1), a detailed study would take place, aimed at reducing the unit cost of electrification. In 2016, it was around £3.5m per single track km and the aim is to slash that to £1.5m, he said.

...read full article

Source: Business Live

[Red Squirrel]

The details are here: https://westofengland-ca.moderngov.co.uk/documents/s7726/Item%2015%20-%20Transport%20Infrastructure%20Projects.pdf

Section 78.4 says:

Survey the Bristol Temple Meads station train shed to prove that it could be
modified to take the loadings of ‘head spans’ or alternative solutions including
those adopted on tram lines (electrification infrastructure). If this is achievable,
it will avoid costly movement of railway signals and ease the impact on the
building’s Grade 1 heritage listing.

Should we be worried to hear the dreaded term 'head spans', or is it OK within the station?

[Electric train]

The details are here: https://westofengland-ca.moderngov.co.uk/documents/s7726/Item%2015%20-%20Transport%20Infrastructure%20Projects.pdf

Section 78.4 says:

Survey the Bristol Temple Meads station train shed to prove that it could be
modified to take the loadings of ‘head spans’ or alternative solutions including
those adopted on tram lines (electrification infrastructure). If this is achievable,
it will avoid costly movement of railway signals and ease the impact on the
building’s Grade 1 heritage listing.

Should we be worried to hear the dreaded term 'head spans', or is it OK within the station?

Head spans in somewhere like Temple Meads station will be fine due to the low speed.

Head spans will be less intrusive than portals or single masts, Paddington and York are good examples of head spans in a grade listed station

[stuving]

Head spans in somewhere like Temple Meads station will be fine due to the low speed.

... and the absence of falling trees, flying gazebos, and flapping fertiliser bags, one hopes.