What is... the Intercity Express Programme? (and what does it mean for the Great Western Main Line?)

The Intercity Express Programme is a £5.7 billion order for building the next generation of long-distance train in Britain. Or at least, that's the theory: its critics would claim it's an overpriced, wrong-headed solution in want of a problem to fix. It all started when someone decided many of our long-distance trains were getting a bit old. It's since morphed into something quite unusual, involving the first major use of electric-diesel "hybrid" trains (though it remains to be seen if that's actually a good idea)...

The High-Speed Train, or HST, also branded as the InterCity 125, entered service in 1977 and will probably still be in service for the rest of this decade. It was and is the mainstay of long-distance inter-city services across Britain; they regularly reach Penzance, Aberdeen, Sheffield, Swansea and many places in between.

They are diesel-powered, and are thus not used much on those routes which are already electrified; but they provide all long-distance services on the Great Western Main Line (GWML), as well as supplementing the fleets used on the Midland Main Line (MML), East Coast Main Line (ECML), and the Cross-Country routes. These days, they are easily distinguished by being one of the last fleets of trains with slam doors. But the HST was never designed to be around for so long; it was a stopgap solution.

As is so often the case, this stopgap solution ended up being a lasting feature of the British rail network. The plan in the 1970s had been for something much grander: the Advanced Passenger Train (APT). Capable of tilting round corners and hitting speeds in excess of 150mph, the APT was forged in the "white heat of the [technological] revolution" so championed a few years earlier by Harold Wilson. Unfortunately, it proved to be a bit too "white heat", and after many setbacks it was finally launched in 1981 while it was still prone to failures. The launch was a PR disaster, and only three production units were ever built, before being scrapped in 1985.

As a stopgap, the BR engineers had decided to build something a bit more conventional; and thus was born the HST. The fleet of nearly a hundred trains, with their distinctive angular power cars at each end, have served the country well for over 30 years now, but they are starting to show their age. While the typical lifespan of a diesel train is 25-30 years, the HSTs have all had their engines upgraded or replaced; nonetheless, asking them to go much past 40 years in service is pushing it.

So, in 2005, the Department for Transport set out to replace the HSTs. In a spectacular lack of ambition, they seemed only to want a like-for-like replacement; one high-speed diesel-powered train replaced by a slightly newer, slightly fancier, high-speed diesel-powered train. Fortunately, someone in the Department woke up to the opportunity that total replacement of the fleet could provide: since the trains need replacing anyway, why not make them electric? And indeed, once the investment in electrification was forthcoming, the need to replace the HSTs like-for-like evaporated.

Rather than scrap the "Intercity Express Programme" (IEP) and simply order some new electric trains to a standard design, the DfT pressed ahead with a revised plan for the IEP. There would be three types of train, all to be built to roughly the same design: electric trains, diesel trains, and "bi-mode" trains, the latter being hybrid trains capable of running off the overhead wires where there were wires, but also carrying underfloor diesel engines to take the train where the wires won't stretch. Eventually the diesel option was dropped, once the full plans for electrification emerged, but the bi-mode option was kept.

Ostensibly, the point of bi-mode trains is to be able to utilise the overhead wires between, say, London and Edinburgh, and then proceed on to Aberdeen or Inverness under diesel power. This means that you don't have diesel trains running "under the wires" for long distances, which ought to save on fuel consumption. But the key benefit of electric trains is that, almost uniquely among forms of transport, they don't have to carry around engines to generate movement. Bi-mode trains, though, mean still carrying around the heavy diesel engines even when you're not using them, and so one of the great benefits of electrification (lighter trains) is lost. It should result in an overall reduction in fuel consumption, but the jury is still out on that.

After a long and torturous bidding process, which was interrupted first by a review into the project's viability after electrification was announced, and then by the General Election and the Spending Review that followed, Hitachi were chosen as the preferred bidders, and would supply over a hundred Super Express trains. They will be built in Hitachi's new factory in Newton Aycliffe, Co. Durham, and marks the first major entrance of the Japanese train builders into the European market.

A total of 866 carriages, in a variety of 9-car and 5-car formations, some electric and some bi-mode, will replace all the HSTs on the Great Western Main Line (GWML) and the East Coast Main Line (ECML), as well as the Class 91 locomotives and Mark 4 carriages on the ECML.

I remain somewhat sceptical of IEP, especially the virtues of bi-mode trains: there are those who would have preferred a standard fleet of all-electric trains, and perhaps use diesel locomotives to haul them where there aren't wires, but I will reserve judgement until the trains actually arrive. It must be said, though, that however you spin it, £5.7 billion is a lot of money for this many trains; standard electric trains would almost certainly have been cheaper.

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Let's turn specifically to their impact on the Great Western Main Line. Combined with electrification, the new trains ought to bring a step change in performance and journey times; but on their own they cannot on their own provide the necessary capacity increase on the GWML.

London to Reading is perhaps the single busiest passenger flow on the whole railway network, with commuters flooding long-distance trains for the non-stop run to London, and making it near-impossible to get a seat in rush hours. If there is to be enough capacity to provide a meaningful increase in seats in the peaks, more has to be done. Fortunately, more is being done. For one, Crossrail's arrival in 2019 will free up a significant number of platforms at London Paddington, meaning they can be used by longer-distance trains instead.

But Paddington isn't the linchpin of the GWML: the biggest bottleneck, by a long way, is Reading. Reading has long suffered from not having enough platforms - fast trains out of London in particular had only one platform available - and too many conflicting routes, with freight trains between Southampton and the north having to cross the main GWML, and with Cross-Country services added to the mix there was never enough capacity. Here's Reading as it looked in 2009 (click to expand):

Reading station layout, 2009

Fortunately, for the last five years Reading station has been undergoing one of the biggest rebuilding and remodelling projects ever undertaken on the British railway network. In a £900 million scheme, five new platforms have been added, and two viaducts to the west end of the station will open next year to segregate east-west traffic from north-south traffic. The scheme, due for completion at Easter 2015, will dramatically increase capacity through Reading, permitting fast trains to run as often as every three minutes between London and Reading. Here's Reading as it will look in 2015 (click to expand):

Reading station layout, 2015

As you can see, the layout of the railway will be transformed. One of the most innovative features is the "Reading Festival Chord" (in light green above), a roller-coaster of a track that goes under the main lines and then over the "feeder" lines from Reading West. What it means is that Cross-Country trains between Birmingham, Oxford and Southampton will be able to reverse at Reading station without ever having to cross the path of high-speed services on the GWML, and that is nothing short of genius on the part of the designers of the scheme.

There is one last part of the puzzle for the GWML, and that is the question of what trains will provide suburban services into and out of Paddington. While Crossrail will take over the stopping services, and the Hitachi Super Express trains (from IEP) will provide the long-distance services, a fleet of electric units will be required for the semi-fast services to Oxford and Newbury, as well as for the branch lines to Windsor, Marlow, Henley and Basingstoke (which will also be electrified).

Here comes the clever part: by syncing up the electrification of the GWML with the Thameslink Programme, no trains need be built specifically for the GWML suburban services; instead, trains will simply transfer from Thameslink over to the GWML. Initially, those were planned to be the Class 319s that currently run on Thameslink, but instead the newly-built Class 387s - which are capable of 110mph, rather than just 100mph - may be transferred; that has yet to be decided.

All told, the Great Western Main Line will be transformed by 2019:

• 650 track-miles of electrification;
• brand-new Hitachi Super Express long-distance trains running between London, Bristol and Swansea;
• electric suburban trains providing fast commuter services from Oxford and Newbury;
• Crossrail services providing through trains from Reading and west London to the City;
• five new platforms and a completely new layout at Reading.

This will enable a "very high frequency" timetable to be introduced - with three or four trains an hour between London and Bristol, compared to just two per hour currently - which should bring a completely different experience to the GWML, just as the very high frequency timetable introduced on the WCML in 2008 has meant I can get from Coventry to London in an hour (a distance of 94 miles), and if I miss a train I only have to wait 20 minutes.

On top of that, following on from the electrification of the GWML, it is planned to electrify the South Wales Valley Lines, a dense network of suburban routes into Cardiff: another 200 miles of track should be electrified by 2020, bringing electric suburban trains to Cardiff and revolutionising rail travel in South Wales - though the details have yet to be worked out.

With all that said, I should point out that not all of the Great Western Main Line will benefit from these upgrades. The electrification will not extend to Gloucester, Cheltenham, Worcester or Hereford; but they will at least benefit from bi-mode trains, capable of running of the electric wires as far as Swindon or Oxford. More importantly, the overhead wires will not go south of Bristol or west of Newbury - meaning all of Devon and Cornwall will remain unelectrified, and indeed will still be served by (refurbished) HSTs, if current plans are anything to go by.

So while parts of the Great Western network flourish, Devon and Cornwall may feel like they're stuck in stagnation. With this kind of scheme, though, there are always winners and losers; in this case it's clear that Bristol, Cardiff, Oxford and the like will benefit from significantly improved journeys to London. And while Devon and Cornwall will not see so much investment immediately, that doesn't rule out the possibility of extensions to the electrification later; indeed, I'd count on at least one major extension to the GWML electrification before 2025.

The Great Western Main Line is going through a momentous phase in its history, perhaps the biggest change since the days of Brunel. It remains to be seen exactly what emerges in 2019, but it's clear there will be faster, more frequent trains - at least for some.

Previous post: What is... Electrification?
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What is... Electrification?

Electric trains are cleaner, quicker, lighter, quieter and cheaper to run. So why is only 40% of the British rail network capable of running electric trains, and the other 60% is still suffering noisy, cramped, sluggish diesel trains?

The simple answer is infrastructure costs. While electric trains are cheaper to run, an electric train must be powered by electricity received through either overhead wires or a third rail. So while the second electric train is cheap to run, all the costs of putting up the overhead wires (or laying down the third rails) and connecting them to the National Grid must be borne before the first electric train can run. Putting up all the wires and transformers for a railway line to take electric trains currently costs about £250,000 per single-track kilometre.

Here's a map showing the parts of the network that are electrified:

British railway network, showing electrification (as at 2012)

First, let's look at the benefits that "electrification" can deliver. With a diesel train, the train must carry around fuel and then generate power by burning that fuel in a diesel engine. But with an electric train, the train can simply tap straight into the electricity, and use that electricity to turn motors. Motors are much lighter than engines, and combined with the savings on having to carry around the fuel, the train is much lighter.

As a result, electric trains can accelerate much faster than diesel trains, making them excellent for suburban routes with lots of stops. What's more, the improved acceleration permits trains to run closer together, meaning more trains can run. Time and again, newly-electrified railways see a significant upturn in usage, often known as the "sparks effect", as improved capacity and speed combine with modern, clean electric trains to yield a much more attractive way of commuting.

The benefits are by no means limited to suburban trains, though: electric trains can pack more power for the same weight, and thus much better performance for longer-distance traffic. It's no coincidence that all the world speed records for trains since the 1970s have been set by electric trains; specifically, by high-speed trains in France and Japan.

Nonetheless, electrifying small, dense, intensively-used suburban networks is usually most cost-effective, since you convert the greatest number of services to electric operation for the least total cost outlay. And thus goes the history of British railway electrification: first to be electrified, in the early 20th century, were suburban lines in Liverpool, Newcastle and south London - all using different (and incompatible) electric voltages and transmission systems. (Indeed, none of them still use the system they first pioneered!)

After the railways were "grouped" into four large companies in 1923, the Southern Railway became the undoubted pioneers of electrification. Having standardised on 660V (later upped to 750V) DC supplied through a third rail, they made a concerted effort to electrify their entire network: by 1939 the "Southern Electrics" covered almost all of south London, running as far afield as Brighton, Eastbourne, Hastings, Guildford, Portsmouth and Reading.

But a committee in 1921 had recommended the national standard should be 1,500V DC through overhead wires; a few lines were electrified using this system by the LNER, such as the Woodhead route between Manchester and Sheffield, but the Great Depression and the Second World War prohibited much progress being made. Overhead wires finally started appearing on the commuter route from London Liverpool Street to Shenfield and Southend Victoria in 1949.

By the time of the 1955 Modernisation Plan, technology had moved forward considerably, and 25kV (25,000V) AC became the national standard for all new electrification schemes. Over time, all the remaining 1500V DC overhead wires were converted to 25kV AC, except those on the the Woodhead route where the line was controversially closed in the 1980s. More importantly, the 1960s and 1970s saw the entire 400-mile West Coast Main Line between London and Glasgow electrified at 25kV AC with overhead wires.

As with many things on the railways, the story at this point inevitably gets tied up with politics. After the success of the WCML electrification and various suburban electrification schemes around London and Glasgow in the 1970s, British Rail wished to embark on a rolling programme of electrification, whereby all the major main lines would be gradually electrified over the course of 20-30 years. Unfortunately, the plan was formulated in 1981, and the Conservative government of the day declined to proceed with the rolling programme in full. To its credit, though, it did fund the electrification of the East Coast Main Line between London and Edinburgh, completed by 1991.

This relatively slow pace of electrification is in marked contrast to other countries in Europe, notably Germany, where they forged ahead with much electrification even before the Second World War, and were more aggressive in replacing steam directly with electric trains, rather than just building diesel engines. Over half of the French, German and Italian rail networks are electrified, while in Belgium and the Netherlands nearly three-quarters of the network is electrified.

Any long-term plans British Rail might have had for electrification were well and truly dashed when, in 1994, the railways were privatised and fragmented. The industry was left without a body like the British Railways Board to advocate for a coordinated national approach to things like electrification. As a result, between 1991 and 2010 only nine miles of railway were electrified: the short link between Stoke-on-Trent and Crewe received overhead wires as part of the West Coast Route Modernisation, to provide a diversionary route for electric trains while other lines were rebuilt.

It has taken the railway network most of a generation to find its voice again. Indeed, as recently as 2007, John Armitt, then chief executive of Network Rail, said that electrification was just another interface to go wrong: too often the overhead wires come down and cause disruption; better to not put them up at all and have a quieter life. In less than five years, though, the view has turned full circle and the government is currently demanding electrification faster than Network Rail can deliver it!

When the Thameslink Programme was approved in 2007, the initial intention seems to have been that the electric trains would simply be moved to a different line with older trains, permitting some of the oldest electric trains to be retired. This "cascade" of trains has long been standard practice, as it allows more than one line to benefit from better trains while only building one new fleet.

But in July 2009, instead of simply shuffling the trains about existing electrified lines, the then-Transport Minister Andrew Adonis approved a plan to electrify new lines in the north-west and the Thames Valley. Once the new trains had been built, the old electric trains from Thameslink would move to the newly-electrified lines; as a result, the lines could be electrified without the cost of building new electric trains. This significant saving is probably the only way electrifying some of the lines could be justified: the cost of new electric trains is not to be underestimated.

The plans were put on hold when the coalition government took over in 2010, but within a year it was back on track. Indeed, the present government has taken a huge liking to electrification, and rather than a rolling programme we seem to be heading for a "big bang", where a huge number of lines will be electrified by 2020:

• a triangle of routes in North-West England, namely the Liverpool-Manchester, Liverpool-Preston and Manchester-Preston lines, as well as the branch from Preston to Blackpool North, will be electrified by 2016;
• the Trans-Pennine route from Manchester to Leeds, York and Selby will be electrified by 2018;
• the Edinburgh-Glasgow Improvement Programme (EGIP) will see the main route from Edinburgh to Glasgow (via Falkirk) electrified by 2016, with other suburban routes in the central belt following by 2019;
• the Great Western Main Line (GWML) from London to Oxford, Newbury, Bristol and Swansea will be electrified in stages from 2016 to 2018;
• following on from that, the Valley Lines in south Wales will be electrified by 2020;
• the Midland Main Line (MML), already electrified between London and Bedford, would have its wires extended from Bedford to Corby, Nottingham, Derby and Sheffield in stages from 2017 to 2020;
• in a project dubbed the "Electric Spine", the lines from Southampton to Nuneaton and Bedford would also be electrified to create an electric freight route for containers from Southampton to the north of England and Scotland.

Let's see that on a map:

British railway network, showing planned electrification by 2020

In theory all of this should be electrified by 2020. However, some parts of the plan are further advanced than others, and you'll note I didn't put a date on the completion of the Electric Spine: it seems as if the Department for Transport saw an idea that Network Rail put forward for possible future electrification and said "ooh, yes, we like that", and approved it before Network Rail had really had a chance to scope out to the project. Nonetheless, the rest of the electrification schemes are proceeding apace, with part of the Liverpool-Manchester line already open to electric trains.

While electrification provides significant benefits - reduced running costs, faster journeys - it doesn't always provide a "step change" without other investment, and the most successful electrification schemes are usually accompanied by changes to track layouts and signalling to unclog bottlenecks in the route.

For example, when the southern part of the WCML between London and Manchester was electrified in the 1960s, a flyover was built at Rugby to allow trains from Birmingham to head to London without interrupting the flow of northbound trains. That one bridge did nearly as much for improving capacity as electrification alone did; together with major rebuilding projects at London Euston and Birmingham New Street stations, they yielded "total route modernisation", and provided for a doubling of traffic on the WCML between 1962 and 1975.

Each of the major electrification schemes planned comes along with various capacity improvements. In the next three posts, I will look in turn at the three big drivers of change on England's railways outside London:

• the "Intercity Express Programme" (IEP) will introduce brand-new Hitachi Super Express trains to the GWML which, combined with electrification, the construction of Crossrail, and the complete rebuilding of Reading station, will totally transform the Great Western Main Line;
• the Northern Hub, encompassing the electrification in the north-west of England and across the Pennines, will unlock capacity through the congested approaches to Manchester Piccadilly and transform rail travel across the north of England;
• the Electric Spine, which technically includes the MML electrification, will (hopefully) transform the future of freight movements by rail across the country.

In the meantime, if you'd like to learn more of the history of electrification in Britain, I'd recommend two booklets on the electrification of the WCML: the first was published in 1966, and the second was published in 1974. Both are preserved on the Railways Archive, a fascinating treasure trove of historical documents from 1830 right through to the present day.

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