That's a very interesting article. However events in the last 18 months seem to show the contracts are not working well, at the top level at least.
One thing I find baffling is the degree of design/supply chain work that these contractors take on.
I was under the impression that NR (with consultants) did the design (Series 1 and 2 etc) and organised the component manufacture, leaving the contractors to roll it out.
But the article reads as though there might be 4 different electrification systems from the 4 contractor teams, all with different supply chains.
How will that work when Carillion takes over the North West project from Balfour Beatty?
NR also owns the GW HOPS train (and other electrification gear), but some contractors have their own systems.
It doesn't seem to be a unified programme to me.
Network Rail and Furrer+Frey have designed the catenary - that's basically everything from the circular steel pile or concrete foundation through to the contact wire, including tensioners, anchor booms, sectioning equipment and so on. EDIT - when I say sectioning equipment, I'm referring to the equipment on the masts/gantries, not the switchgear in cabinets at ground level.
That forms what is essentially a catalogue of components made available to the individual electrification teams at the point of installation and then to Network Rail or their maintenance contractors onwards after completion and sign-off.
The intention is that the small part steelwork is as standardised as possible with special design elements being carried by the mounting brackets and not the catenary components. You can see this approach at places like Thatto Heath Canyon, where we've mounted the top ten feet of a mast directly onto the cutting wall, and then mounted cantilever arms onto the section of mast, so the cantilever arm is a standard component no different to those on normal masts.
The route design work is undertaken by a third party, such as Atkins and/or Parsons Brinckerhoff. They'll have geology reports, groundwater analysis, gauge data and radio survey data from Network Rail, signalling runs, cabinet locations and other structure data, where each mast will be sited, what components are needed for each mast, if special locations such as listed buildings require different catenary (such as Rainhill) and so on. Mast location relative to the track will dictate the reach of the cantilever arms, S&Cs will dictate mast type and additional cantilever arms and additional tensioning to be installed, availability or not of an anchor point for the tensioner will dictate additional masts or additional cantilever arms to feed the wire to the point where it can be tensioned and so it goes on.
There's electrical design work, which is co-dependent on the route design work. It takes into account the power draw/demand/load requirements and using data on the National Grid's HT capability, and surprisingly, things like Environment Agency data on flooding, data on SSSIs etc, will determine the most appropriate points for feeders, how many are needed, what, if any existing power supplies can be utilised, where ATF is needed, where sectioning and neutral sections will be installed and so on. The electrical design has to work with the route design - clearly you can't have a feeder or sectioning cabinet at Sydney Gardens in Bath and it also has to take into account engineering access points and typical possession lengths, route options for diversions, where to site neutral sections to have the lowest risk of trains coming to a stand in a neutral section, that sort of thing.
There will also be EM interference modelling of the electrical design and if necessary, additional filters will be specified, though transformers produce a much cleaner and more stable supply these days. The ECML electrification final report is a bit of an eye opener on how bad things were just 25 years ago, when we could only complete the ECML electrification through stand-by feeding arrangements around Edinburgh and Berwick area.
The new electrification schemes also have SCADA monitoring to take into account and that needs to be thought about too.
When a viable design has been completed, the route design people will generally do a 3D visualisation of the route and assess signal sighting issues, getting feedback from TOC drivers/driver managers and union representatives when needed, and if issues are flagged up, plan either the relocation of signals or the use of alternative structures - could be a twin track cantilever instead of a pair of masts, that sort of thing.
There's all the usual safety checks, height at level crossings, what crossings might be better closed/replaced by footbridge, platform safety, designated earthing points and so on to take into account too.
There's also some areas where Furrer+Frey will do some or all of the design work themselves, as part of the project. That's frequently the case where things like the rigid overhead conductor system is used, and they tend to be involved when non standard components are used - different masts, mounting brackets and the like.
When the design is signed off, the contractors and design team can begin the process of ordering components, but until the design is signed off, it's not known exactly what components will be required and in what quantity, whether there will be custom fabrications required. Small changes, like moving the tensioning equipment or adding an extra crossover will dictate different components, a crossover will require additional cantilever arms and will have different (non standard) registration arms, so it's not something that can be an afterthought.
The changing of contractors shouldn't present an issue - it's construction industry stuff, staff will jump ship if they don't want to move with BB and everybody has their own equipment, I wouldn't expect any significant delay with the swap from BB to Carillion/VolkerRail. They're all professionals, toss them a set of drawings and they'll do what the drawings say, doesn't matter if they use slightly different equipment, as long as the end result is in specification, that's really all that matters. The chances are they'll be using very similar or identical equipment anyway - there's not many piling rigs and other rail mounted equipment which fits the UK loading gauge in any case. RRVs generally come from an 'rental' supplier and I'd expect the sales manager to be trying to get the new contractors to rent the exact same equipment.
