Holy Grails and Thameslink Fails (Part 1): A Brief History of Thameslink


To understand the current issues with Thameslink, one has to understand its past. In this series, we explore the history of London’s only ‘through’ line and how that influences today.

For many years it has been the Holy Grail of urban rail systems to have railway lines starting on one side of a city and emerge on the other side. It wasn’t always this way. In the days of steam, going underneath a city (and having underground stations at all) was generally thought to be impractical. Indeed for some time only London was bold enough, or mad enough, to do such a thing on a serious scale. Even then the heart of the city wasn’t really penetrated, with a single exception – one that would ultimately make Thameslink possible.

Paris waited until electric traction became available, pioneered in London of course, before it was prepared to embark on building the extensive Métro and its multitude of individual suburbs-centre-suburbs lines. Vienna did have a steam-operated underground section of line for a short while, but was quick to convert it to electricity once that became an option.

A worldwide trend

Today, worldwide but especially in Europe, the situation has changed completely, as major urban conurbations realise the benefit of through cross-city services. There is an ongoing trend to get rid of (or at least reduce the size of) termini and, in so doing, create more through journey opportunities. Alternatively, an original terminus might be replaced with a through station, such as happened at Birmingham Moor Street or, on a much more dramatic scale, in Vienna, Madrid or Berlin.

French-style RERs remain an option for providing cross-city links, but mostly involve large-scale main line sized tunnels costing billions, as seen in Berlin, Madrid and, of course, Paris. One could put Crossrail into this category as well, but that also has a strong element of providing service entirely within the central area – much more so than Thameslink.

As well as reducing, or eliminating, capacity issues and operating challenges at termini, through services mean better utilisation of rolling stock. Whilst building an entirely new line is, in railway operating terms, relatively simple to introduce, joining two existing lines at opposite sides of a city and smoothly integrating them into the existing railway system presents far more of a challenge.

Multiple examples of Thameslink-lite

Such joining together is not entirely new in Britain. Nor is it limited to London. There are cases where services that used to terminate at a central station are joined together to create a through train service (such as Merthyr Tydfil – Bridgend via Cardiff, or Barnstaple – Exmouth via Exeter). In Liverpool we have the link and the loop line on MerseyRail and in Scotland there is the re-opened Argyle Line in Glasgow.

Manchester now has the potential to benefit from through services as the Ordsall Chord has recently been opened and is used by trains to link north and south Manchester. Unfortunately, the recent experience of Northern commuters has re-enforced the view that joining two previously unconnected services does not always proceed smoothly.

In London, sentimentalists may mourn the loss of Broad Street terminus, but its abandonment has made possible a cross-London service of sorts on the London Overground (currently 16tph but this should go up to 20tph in the next few years). However, this does not quite fit our criteria. It doesn’t quite go through what is generally regarded as the city centre and there was no existing service on the north side to link up to. Although it utilised abandoned railway infrastructure, in operating terms, the extension of the East London line northward was effectively an extension of a dead-end branch line.

Another example in south London that doesn’t quite qualify is the combining of the Wimbledon – West Croydon rail service with part of a line terminating at Elmers End. This created a through service via Croydon town centre. In this particular case, the objective is the same but is achieved by converting under-utilised rail lines into tram lines and creating a new cross-town link using existing streets. The complexity of fitting the new service in with existing services was avoided, because there are no other tram services it needs to be integrated with – and in any case the situation with trams, which are generally driven on line of sight, is much simpler.

The early origins of Thameslink

As early as 1866, just three years after the Metropolitan Railway opened the first passenger underground railway in the world, the London, Chatham and Dover Railway built a line northward from today’s Blackfriars. This joined up with the Metropolitan Railway’s widened lines at Farringdon (then Farringdon Street). Despite not being its primary purpose, the route was a busy passenger corridor until trams were electrified and provided stiff competition. However the passenger services were mainly about accessing the City, with a triangle built to reach Moorgate.

During World War 1 the passenger service was stopped as a temporary wartime measure, as was the case with many railway lines. Here, it was probably more due to a desire to maximise freight running, rather than as an economy measure. Whatever the initial reason, it would be more than 70 years before passenger services resumed. The route was abandoned as a freight route in 1969.

The regional mafia on British Rail

At the time when the Snow Hill tunnel through central London was abandoned, the railways in Britain comprised of various regions which reported to the British Railways Board. All railway employees worked for the nationalised industry – except, slightly paradoxically, the members of the British Railways Board, who were employed by the Ministry of Transport.

All the English railway regions had termini in London. These regions were well-known for acting independently from each other and co-operation was minimal. Although it was arguable that the situation should not have been allowed to develop the way it did, there was some logic behind keeping it that way. Traction systems on different regions were quite different and generally incompatible. Western Region was entirely diesel. Third rail was originally only found south of the River Thames. Electrification north of the Thames was generally overhead electrification at 25kV but there were pockets of fourth rail electrification – eventually changed to third rail.

The days of the paper timetable

Possibly more relevant to current events, creating a workable national timetable was incredibly complicated. In those pre-computer days, it probably made sense to construct timetables at regional level with a minimum of interface necessary for various inter-regional trains that, on the passenger side, were few and far between. On Southern Region timetabling generally went down to divisional level – there were three divisions in Southern Region. Central headquarters would be responsible for co-ordinating publication of the national timetable, and resolving any inter-regional disputes that there may be but, in broad terms, the regions wrote their own timetables and operated them.

As there were then no computers suited to the task, a significant amount of manual effort was involved in creating the Great Britain National Timetable each year. This had to be printed and distributed in good time for the main annual timetable change. Because of this, the exact times of trains were pretty much fixed months in advance. Roster clerks and depot managers would have a number of months available to prepare for the change. They would know, for example, the exact timing of trains, when they were due to leave the depot and exactly when they could reasonably expect them to be back in the depot. It is worth noting that the main timetable change was in May then, as opposed to December now. This was later moved to December to coincide with the common change date in Europe because at that point timetable changes impacted on Eurostar and hence the French national timetable. Once HS1 was fully open, the need to align with Europe over this matter diminished and we seem to be heading towards a situation, not entirely by design, where May is becoming the main annual timetable change date once again.

Network Southeast breaks the mould

In 1982 the management structure of British Rail shifted from the regions to ‘sectors’. The London and South East sector was born as part of British Rail’s ‘sectorisation’. It was clear that one of their objectives was to break down the regional barriers. Although the regions still existed their role was now to provide services to the sectors, who paid them for their services. In other words, the regions no longer called the shots. In 1986 the sector was marketed under the name it is generally remembered as – Network SouthEast.

An obvious way of breaking down the regional barriers and of displaying Network Southeast as an entity, was to re-open the abandoned Snow Hill tunnel and extend the proposed Bedford-St Pancras electric service to Blackfriars via Farringdon over the reinstated track. From there it could continue via either London Bridge or Elephant & Castle and, in so doing, take over some existing Southern Region services – by now rebranded as a Network SouthEast service of course. There would be the challenge of the trains needing dual traction (pantograph and third rail pick-up shoe) but traction technology had reached the stage where this was considered do-able, even though it had never before been attempted on British Rail on such a scale with full integration with other services – though since 1976 the Moorgate service used dual-voltage trains over the short section from Drayton Park to Moorgate but at restricted speed when on third rail.

Getting the original scheme authorised

It was fortunate in that Thatcherite era that the Treasury approved of the scheme. This was partly because of the efficiencies achieved by avoiding layover of trains at termini. In truth though it was also because it reputedly only cost £4 million to implement – a relatively tiny sum of money even in those days.

This small sum of money needed to create Thameslink did not include the cost of new dual-voltage rolling stock but most of that cost of this would have been necessary anyway for replacing old stock on other lines – something that could now be done by utilising the displaced Class 317s which would be replaced by the new Thameslink class 319s. So, for the most part, rolling-stock cost did not feature in Treasury calculations for reopening the line.

It is hard to establish exactly who contributed what to the project in financial terms, but it seems that the Treasury paid for the line to be reinstated so that trains could run from Blackfriars to Farringdon and rolling stock utilisation could be improved.

In addition, the GLC contributed £1.4 million. This appears to have been for additional passenger benefits and may have included money towards preparing for a new City (then St Paul’s) Thameslink station. Despite this, the GLC always appeared to claim credit for the whole scheme.

It seems that no consideration was given by the Treasury to any passenger benefit of the scheme when considering its merits. Introduction was initially very low-key, and that may have been wise with a generally anti-railway prime minister. This was a common railway tactic of the era – to get projects approved ‘under the radar’ and not attract too much attention in government circles. Indeed government involvement in actually introducing the scheme was non-existent. Their only job was to authorise it and provide the money to enable it to happen. Once the scheme was authorised, the government did not want to get involved and was happy to leave British Rail to get on with it. This did leave everyone in no doubt from the outset that, if things went wrong, Network Southeast would have no-one to blame but themselves.

Cheap, cheerful – and it worked

The original Thameslink scheme may have been built on the cheap, but it worked. Any issues of serving London Bridge station in peak hours were resolved simply by… well.. not serving London Bridge station in peak hours (except for a 1tph token service).

The original service was a mere 4tph for most of the day but 6tph for a one hour peak. Initially there could be an awful lot of recovery time built into the service through the central section. This considerably simplified the timetable challenge and help ensure that trains were handed over on time when joining an existing network.

When it came to integrating with existing services it was a different world then. South of the river, the Thameslink trains using a third rail pick-up had similar characteristics to the existing third rail stock on Network Southeast. As existing train paths were being re-purposed, rather than any new ones created, there was not a capacity issue.

No problems with the Midland Main Line

North of the river, things were also very different then. Despite both Thameslink services to Blackfriars and a residual service to Moorgate, the Midland Main Line into St Pancras was not exactly taxed, capacity-wise. Initially, with loco-hauled Inter-City trains limited to 100 mph and four tracks between London and Bedford, the 100mph Thameslink class 319 electric trains that used the fast lines could hold their own against the the other services they had to integrate with. Integrating 6tph, later 8tph, into the Midland Main Line would not have been challenging.

Even the introduction of the HST on the Midland Main Line did not change things significantly, as line speeds limited them to 100 mph. This may well have been influenced by the agreed maximum speeds that could be in operation on single-driver trains. It was not until 1988 that HST’s were used here to their full potential. The rewrite of the timetable was assisted by the ability of the Thameslink trains to accelerate quickly compared to their diesel predecessors. Thameslink wasn’t the problem – it was the solution.

Learning by route

The necessary route learning for drivers – one of the biggest problems today – must have been absolutely minimal. The distance between Farringdon and Blackfriars was just less than one kilometre. So, in principle, a driver from north of the river who had additionally learnt that short section of route could take the train as far as Blackfriars where a driver from south of the river with suitable route knowledge could take over and drive the train to its destination.

In practice, a single Thameslink driver took the train over the whole route and, in doing so, avoided the complexity of having drivers changing mid-journey. In those days there were generally sufficient available drivers for training, drivers were more willing to work overtime and regulations concerning drivers hours were less strict.

The dual-voltage dual-purpose railway is born

One of the first three routes was a limited stop service from Bedford to replace a similar service that was well-established. It seemed logical to combine this service with a similar service from south of the river and so a Bedford-Brighton service was born. In doing so, this firmly established Thameslink as, at least partially, being about running longer distance trains rather than the more usual suburban services that normally operate through central tunnels under cities.

The mix of longer-distance and suburban services (and city centre services similar to the Underground) was going to create challenges in future. And any future rolling stock was inevitably going to be a compromise. As plans progressed for a future enhanced service preference seemed to given to longer distance routes based on the concept of the Bedford-Brighton service.

The preference for Thameslink joining together routes that serve towns and cities a considerable distance from London will lead to a strange situation at London Bridge for those trains that have come up the Brighton Main Line. Most longer-distance trains will be through trains and all suburban services will terminate there – a reversal of conventional wisdom. This must be partly brought about by the fact that 12-car trains can be used on the longer routes but suburban routes on Southern are generally restricted to 8-car or 10-car trains. With capacity becoming the big issue driving the present-day scheme (it wasn’t originally) this is a very significant consideration.

Thameslink – too good to leave as it was

We will not go into details here of the history of the development of the Thameslink Programme, as we have covered it many times before, but suffice to say it seemed that to try to run more and longer Thameslink trains was a good idea that had plenty of potential. Furthermore, an enhanced scheme could have significant effect on providing the extra capacity much needed on train services in London.

The result was the Thameslink Programme – a much delayed and enhanced version of an earlier Thameslink 2000 scheme. In very simple terms there was a construction phase and an implementation phase. The construction phase is now largely complete apart from some signalling enhancements and we are now into the implementation phase. A critical risk was that, during the construction phase, a challenging timetable would have to be introduced.

Thameslink Programme Construction Phase

Having taken a look at how it was relatively simple to implement the original Thameslink scheme we now take a very brief look at the Thameslink service pattern during the present project’s construction phase.

The train service during the construction phase on Thameslink, Southern and SouthEastern was really one based around the constraints of construction. These included:

  • Various platforms at London Bridge being out of use – though in some cases through services could go though London Bridge but not stop there
  • Thameslink trains not being able to travel via London Bridge at any time of day.
  • Terminating platforms at Blackfriars being unavailable

The final constraint meant that, in order to maintain any kind of meaningful service to Blackfriars, more trains had to travel through the Thameslink core. This led to a 15tph peak-period Thameslink service through central London terminating at various locations on on the Midland Main Line (generally Kentish Town, St Albans City, Luton and Bedford).

Whilst rail travellers probably do not have fond memories of this period, and the many problems that developed during it, as far as the Thameslink timetable is concerned, it was fundamentally sound.

In a way, the fact that timetable worked is quite remarkable. The ultimate intension is to have 16tph Thameslink trains going to various destinations on the Midland Main Line and yet for the past few years there has already been 15tph using older, less-suitable rolling stock rather than the modern class 700 trains specifically designed with the Thameslink route in mind.

Nearly there

The Thameslink Programme project is due to complete in 2020 with the introduction of the timetable that will see all proposed services implemented. Meanwhile, the first stage involved in building up to the 2020 timetable has just been implemented. In essence, it involved shifting services to their final pattern, reintroducing running through London Bridge and the introduction of just 3tph extra through the core section of Thameslink. These 3tph would go onto the East Coast Main Line rather than the Midland Main Line. The objective seemed relatively modest in relation to the entire programme and, one would have thought, would not have been too difficult to implement. But…

In part 2 we will look at how the new Thameslink service went horribly wrong.

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Written by Pedantic of Purley