Euston Amalgam – a combination of Euston Express station for Euston and modifications to HS2’s approach tunnels.

30 November 2016

Summary

Further discussions with the Department for Transport, HS2, Network Rail and others persuaded the Euston Express team to examine an alternative scheme which retained the E Ex scheme for Euston Station, with all tracks for WCML and HS2 within the station width, but connecting to the longer tunnel design of HS2 to avoid interfering with the WCML between Queens Park and Primrose Hill tunnels.

This is not only possible but also removes the need for the ‘Birdcage’ grade separation opposite Park Village East, and much reduces the effect of construction on WCML which, for the AP3 scheme, were severe.

This is described below as the ‘Euston Amalgam’, a combination of Euston Express station for Euston and modifications to HS2’s approach tunnels.

Cost estimates have changed, since the scope of both schemes has altered, but the like-for-like saving of the Euston Amalgam scheme compared with the latest version of AP3 is estimated to be £4,721bn.

Background

Euston Express presented, through petitioner Sam Price(Petition 691), an alternative scheme for HS2’s route and terminus at the London end. It comprised:

  • a short tunnel from Old Oak Common to join the West Coast Main Line near Queens Park Station, two-thirds shorter than the HS2 tunnels.
  • HS2 trainsthen using the ‘fast’ lines on the WCML into Euston.
  • WCML trains using the other two pairs of tracks, including slow WCML services sharing with the ‘DC’ trains from Watford to Euston, between Queens Park and Camden Junction (they already share from there to Euston).
  • There would be agrade separation for the Bakerloo and Overground trains west of Queens Park station, while some bridges and tunnels would have their height raised to accommodate W10 gauge freight trains which would use the current ‘DC’ tracks.

Nearer to Euston, four WCML tracks (called lines A, B, C and D) at Upper Park St Tunnel would lead into a ‘throat’ track arrangement to access 12 platforms requested by Network Rail for the WCML trains. The HS2 trains would use Tracks E and X through Lower Park St Tunnel, before widening into the throat for 11 HS2 platforms.

Euston Expressproposed that the Euston station, comprising 23 platforms within the current station width, would be an integrated whole for all passengers, rather than two separate station at different track levels. A 24th platform would be achievable, if asked to achieve 13 WCML platforms, by encroaching into Melton Street – which is already foreseen as being shut with the HS2 AP3 scheme.

Euston Express would provide a level deck across the whole station, as desired by Camden Council, although positioned higher than local ground level, in order to avoid at least hundreds of £ millions of costs for extra excavation and track level changes, and a large increase in spoil and lorry traffic.

The estimated cost saving for Euston Express as compared with HS2 AP3 was quoted as £1,850 m at 2015 4th Quarter prices, based on a 23 platform station.

This excludes further large scale costs imposed by Camden Council’s desire for lowering the WCML track and approaches to create a ground-level pedestrian deck.

The above scheme was presented to the House of Lords Select Committee on 11 October 2016 and the above costs were not challenged by HS2.

Further discussions with HS2, DfT and Network Rail

Since the Select Committee hearing, Euston Express has had further discussions with HS2, DfT and Network Rail. From these meetings, it appeared that views had changed on certain issues. Concern was also expressed about the ability of a throat suitable for HS2 train lengths and speeds to be designed within the area south of Park St Tunnels without grade separation as provided by HS2 in the ‘birdcage’ opposite Park Village East.

Although Euston Express considered that a throat would be possible ‘on the flat’, train speeds would have been reduced and there would be less flexibility to accommodate late arriving trains, more likely from the longer journeys such as from Scotland.

Secondly, Network Rail West Coast Main Line has more recently expressed strong concern about the disruption to the passengerservices during construction of HS2, both about the works needed for Euston Express around Queens Park and inwards, and also the even greater disruption needed for the HS2 AP3 scheme, and the construction of the birdcage.

Euston Express understand that an alternative scheme without the birdcage has been discussed with some residents, but we have no information on it and cannot therefore comment.

The Euston Express team has been discussing alternatives to enable the best of both schemes, keeping their existing design for Euston station at the present Euston station level, but connecting the HS2 tracks to two or more tunnels roughly on the route of the proposed by HS2 tunnels from Old Oak Common. This we call Euston Amalgam, described below.

Euston Amalgam

The throat and portal area

In discussions with HS2, it became clear that there was a strong preference for three tracks for some distance north of the ‘throat’, effectively to split the station ‘up’ tracks to serve 5 and 6 platforms each, and allow a platform occupation ‘refresh’ time of 3 minutes. This distance relates to the approach speeds of trains, length of trains and rates of acceleration and deceleration.

This three track aspiration is fundamentally different to earlier thinking by HS2. Essentially a central ‘down/northbound’ track would be accessible from both groups of platforms, with an ‘up’ track on either side, with those tracks splitting from the ‘up’ line some distance away from the throat.

At some point the central ‘down’ track will need to cross one of the ‘up’ lines (using grade separation like a motorway junction) in order to provide a more usual ‘left hand’ running line towards the north. The design assumes that trains will generally depart on time, but that arrivals may be less reliable; hence the two parallel ‘up’ tracks to be better able to regulate incoming trains.

Network Rail has already proposed such an arrangement elsewhere on main line terminal approaches to London (eg for Paddington where fast line train frequencies are intended to become 24 trains per hour each way around the mid 2020s). HS2 is only proposing 18 tph in present plans, so such an arrangement would be ideal to accommodate the full HS2 train service and also allow for late running trains from the North West and Scotland, if operational variations continue to be a problem.

Euston Expressthus proposed that there should be, for the approaches, two ‘up’ tracks with one departing ‘down’ track between them. There would be these three tracks for HS2 from Park St Tunnels inwards as a minimum distance. The three tracks would open out into the 11 platforms between that point and the end of the platforms.

We assume that there is a preference for three tunnels somewhat North of that point, necessitating a junction between two tunnels underground (generally called a Step Plate Junction or cavern) which is a normal part of tunnel construction; its size and cost depends on the design speed of the tracks, so this needs to be reasonably close to Euston toavoid reducing the speeds of the trains further than necessary from the station. Options and routes for thetracks, tunnels and portals are described further below and shown on the attached line diagrams.

As for levels, the critical ones relate to the ability of tunnels to rise to the level of the existing station platforms, if HS2 is to be made to operate generally within the present terminus location and levels. We assume that any new tunnel in the Park St Tunnels area would be roughly to the profile of the upper HS2 track in the Birdcage. The gradients would be similar or flatter than HS2 AP3 propose, and both would accommodate turnouts and crossovers.

Network RailWest Coast Main Line has stated that they need as many tracks as possible into and out of Euston, both during construction of AP3 and when complete. They currently have five main tracks from Camden Junction but with a difficult and slow speed series of junctions, and some ‘single lead’ tracks which prevent trains entering and leaving simultaneously on parallel tracks. This is inefficient, and also hinders operations when arriving trains are running late.

The five tracks serve 18 platforms at present but, after HS2 is complete, NR has requested 12 (and desirably 13) platforms because there would be fewer long distance trains (the most unreliable) when HS2 is complete. As we have pointed out before, the turnaround times of some trains at Euston are the most relaxed of any London terminal.

So we believe that four tracks for WCML traffic from Primrose Hill Tunnels inwards, when reorganised for parallel entry/exit on the throat and with a similar three-track layout as HS2 for fast line trains, will be more than sufficient for the planned number and type of trains. However, bearing in mind the above comments, we propose two options, one with five tracks for WCML, and one with four for WCML and a fifth track shared with HS2. These are shown on the diagram as Options 2 and 1 respectively.

Option 1 – Shared approaches

The HS2 tracks (red) and the WCML Tracks (blue) from West to East are laid out as follows:

  • Westernmost HS2– inbound (up) for the five or six easternmost HS2 platforms. In tunnel from a junction somewhere beyond the Carriage sidings to come to the surface at location P2. Around half of the HS2 service (~9 TPH) would use this line.
  • Centre track HS2 – outbound (down) for all platforms (18 TPH) to use Track E through Lower Park St Tunnel and then drop down on the alignment of an enlarged ‘Rathole’ tunnel portal,to go under the canal and enter the westbound HS2 tunnel.
  • Easternmost HS2 – inbound (up) to rise from the cavern junctionto a portal in the Carriage sidings, then on existing WCML Track X over the canal and through Lower Park St Tunnel, to carry ~9 TPH.

Portal locations P1 and P2 betweenPark St Tunnels and Park Village East

Between the canal and Park St Tunnelsthe easternmost HS2 via Track X is joined by one of the up fast WCML tracks to share capacity through the tunnel.

  • That WCML joining track would have sufficient approach length to retain trains between the WCML main line and the section of track shared with HS2, so that either the HS2 or WCML train could be held out of the way if running late with another train approaching. WCML trains would be around a third to a half of the eventual WCML fast lines services - ~5-8 TPH.
  • The main WCML ‘down/northbound’ track would become Track C, while leads to ‘right hand’ running after far as where (probably near Willesden), it would switch to LH running northwards. This offers a further operational benefit for Network Rail WCML, noted below.
  • The Euston Express team suggest that the Line X connection should be relocated at its southern end between tracks C and B (instead of to the east of Track A, as now) to increase theflexibility of the WCML throat. Track D would be the second WCML fast line approach to the terminus. An equivalent to a flying junction is created that way, with northbound trains all exiting (as with HS2) on the central Track C, on the basis that departures from the terminus should be more reliable than those arriving from a long distance north.
  • Commuter trains on revised Tracks A and B would have a standard throat as adopted elsewhere at main line London terminal platforms such as Victoria and Liverpool Street.

Network Rail West Coast Main Line has expressed a strong desire for a secondary means to send out-of-course trains away from Euston other than on the fast tracks, in order to clear platforms and make space for more trains arriving. Part of this concern should be mitigated by the proposed Euston Amalgam three-track solution.

However, it would also be possible to route some departing fast line trains not onto Track C but onto the parallel down slow line Track B, and so enable two fast line trains to depart simultaneously, one onto C and the second onto B. As the tracks would be parallel, it would be an easy matter to provide a B to C crossover distant from Euston, to allow the second train to switch over to the Track C fast line before that itself switched back to LH running. This option is shown on the accompanying diagrams.

Because Option 1 uses Tracks E and X through the Lower Park St tunnel, it would not be GC-gauge capable, unless that tunnel were enlarged. This is no different to the basic Euston Express proposition, for classic compatible trains only.

Option 2 – separate approaches

The HS2 tracks (red) and the WCML tracks (blue) from West to East are laid out as follows:

  • Westernmost – inbound (up) for the five or six easternmost HS2 platforms. In tunnel from a junction west of the carriage sidings to come to the surface at location P1.
  • Centre track – outbound (down) for all platforms to enter a tunnel at location P2 on the stub end of the siding.
  • Easternmost – inbound (up) to go in tunnels from the junction west of the carriage sidings, to the surface there, and run on existing WCML track E over the canal and through Lower Park St Tunnel (classic compatible gauge only).

This arrangement would create two new tunnels into the Euston throat area, so could permit GC gauge operation through the new tunnels and into half of the Euston HS2 platforms. It is currently foreseen by HS2 that GC operation might be desired in the long term for about half of the HS2 service frequencies, so this would be compatible.

The WCML tracks (A, B, C, D and X) would remain as they are now, thoughwith Track C becoming the new fast ‘down/northbound line’ to permit greater flexibility for arriving and departing trains. As above, it is suggested that Line X should be relocated at its southern end between tracks C and B to increase the flexibility of the WCML throat.

The secondary fast line exit from Euston via the down slow line would still be available.

Hampstead Road Bridge

We see no change needed for Hampstead Road Bridge compared to Euston Express.

The Station

Euston Amalgam would use the same station design proposed as for Euston Express for HS2 and WCML trains.

Costs

The costs presented to the Select Committee on 11 October 2016 were as follows:

The following changes have been made since then to the scope of the projects:

  1. Euston Amalgam – longer tunnels to avoid altering WCML tracks etc. underground cavern and then three portals nearer to Euston; station remains the same.
  2. HS2 – AP3 – it is understood that an alternative approach is being developed, removing the birdcage dive-under opposite Park Village East, and substituting an underground cavern and three portals nearer to Euston, with the station remaining the same. Details of this are at present sketch.
  3. It is still unclear if the cost of land take and compulsory purchase is included in the AP3 estimate. If not, then the cost could increase by around £1,000m to £8,815.

HS2 AP3 revised Euston Amalgam Saving

Overall cost£ 7,815m £5,158m£1,657m

What do you get for this?

New station for HS2 Yes Yes

New station for WCML No Yes

If it were possible to provide Euston Amalgam for just the HS2 part, the Euston Amalgam cost would be say 60% £3,094. This means that, for HS2 related work, the Euston Amalgam solution is £4,721m cheaper.

Conclusion

We believe that either of these compromises will satisfy the ‘reasonable requirements’ of both HS2 and Network Rail WCML, both being considerably cheaper than the AP3 scheme. The two Options offer alternatives depending on the willingness of the two infrastructure managers to co-operate, and possibly save money and improve the flexibility of their operations.

It may help the cost-effectiveness of both Options, now that the Department for Transport has defined that the designated train operator will be responsible for both the WCML and HS2 operations at least into 2030, so should be able to take a consolidated view of the requirements for reliable Euston approaches for both groups of services.

Option 2separates WCML and HS2 traffic so, in theory, there is no need to make any significant changes to the approaches of the WCML part of the station. Howeverwe consider this is an opportunity lost for WCML traffic and their passengers, in future years, to minimise perturbation and maximise capacity when the portents are that the ‘near Shires’ and the Home Counties’ end of the classic WCML are becoming commuting territory for London on the same scale as the South West Main Line.

Clearly, further discussions need to be held with HS2, Network Rail and the Department for Transport to agree a scope and refine the costings, but the differences remain very high – and growing.

Further information:

Sam Price, petitioners Sam Price, structural engineer, .

Jonathan Roberts, Railways expert,

Michael Byng, QS,

Lord Berkeley, House of Lords, ; 07710431542

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