die belebende Bedenkung

HS2 is a big draw

with 2 comments

At this early stage, eight months into Network Rail’s current five year funding period [Control Period 5], the cost estimates of many of its programmes have not yet been determined, said rail minister Claire Perry on December 16.

[Railways: Infrastructure: Written question – 218298, response by Claire Perry]

Network Rail continues to develop the Rail Investment Strategy programme with the Department and review costs with the Office of Rail Regulation. The Transport Secretary has been clear these projects should be delivered within the overall Network Rail budget. The latest cost estimates (in 2012/13 prices) are listed below, though not all of these programmes have been through the Office of Rail Regulation’s cost scrutiny process (“Enhancements Cost Adjustment Mechanism”):

(a) Reading Station Area Resignalling and Remodelling, including the new station and maintenance depot: £895m is Network Rail’s anticipated final cost when the scheme completes at Easter 2015

(b) East West Rail Phase 1 (Oxford – Bicester) – Network Rail estimate of £318m

(c) East West Rail Phase 2 (Bicester – Bletchley – Bedford) – currently at an early stage of development

(d) The Northern Hub – funding commitment of £600m, programme still in development

(e) TransPennine electrification – funding commitment of £300m, programme still in development

(f) Great Western Mainline electrification – Network Rail recent estimate of £1.7bn

(g) Midland Mainline electrification – Network Rail recent estimate of £1.3bn

(h) South Wales Mainline electrification – the section from Cardiff to Swansea is at an early stage of development

(i) Valley Lines electrification – at an early stage of development (sponsored by the Welsh Government)

“At this early stage”? Great Western Main Line part-electrification was announced by Andrew Adonis on 23 July 2009. If its estimate has risen from £1 billion to £1.7 billion, that should be setting off alarm bells about the cost of HS2. The GWML wiring is only for 225 km/h linespeeds. HS2 electrification would need to be much beefier, to cope with its much higher train speeds, and much larger current draws.


Written by beleben

December 19, 2014 at 10:48 am

Posted in High speed rail, HS2

2 Responses

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  1. So how much power does the catenary need to provide? Sorry this is a bit longer than a comment!

    HS2 appear to have relied heavily on data for an Alstom AGV-11 200m train, which they call their “Reference Train”.

    A Google search showed two FOI requests for information about this train and its performance and energy.
    21st Feb 2011 FOI-124B Regarding HS2 Traction Energy Modelling

    24th June 2011 OI11-188 Regarding train speeds

    Neither of these answered the request fully. HS2 claimed that they could not release the Alstom data because they had signed a confidentiality agreement. However, both responses refer to an Attachment 1 which is an Alstom brochure including a traction curve. Unhelpfully, and perhaps intentionally, the FOI responses do not provide a link to that attachment.

    However, there is a link to an AGV brochure containing (on page 14) a traction curve here:-

    The traction curve data is for a single 410 tonne, 200m, 11 coach, articulated train with 6 traction units. The traction curve shows the Tractive Effort that can be produced by the train at various speeds. The Tractive Effort reduces from its maximum of 272KN (below about 77kph) to 95kN at 360kph, which is the train’s maximum speed. The graph also shows the force needed to travel on level track and up various gradients. The force needed on level track corresponds to the drag on the train, and this increases rapidly from 33kN at 225kph to 74kN at 360kph.

    With a bit of maths it is possible to calculate the power needed from the Tractive Effort and speed. It is also possible to calculate the rate of acceleration from the mass and the force. The calculation shows that to maintain a speed of 225kph on level track requires 2.0MW but at 360kph the power required is 7.4MW. The train’s maximum power is 9.5MW, which is reached at speeds above 310kph. At 310kph this power is sufficient to produce 110kN of Tractive Effort to overcome a drag of 56kN, so 56kN is available to accelerate the train at 0.13m/sec2. At 350kph the Tractive Effort has fallen to 98kN and the drag has increased to 70kN, so only 28kN (half that at 310kph) is available to accelerate the train. Acceleration above 350kph is therefore a leisurely 0.07m/sec2, and it will take around a minute and 4km to reach the maximum speed of 360kph.

    HS2 plans to run these trains in pairs for some services. Running in pairs would avoid the frontal drag from the second unit but most of the drag is likely to come from the rest of the train. It therefore seems possible that the power required to maintain 360kph on level track could be around 14MW. It would need around 18MW to accelerate a double length train to its maximum speed as quickly as possible.

    Of course, HS2 Ltd has “future proofed” the alignment of the line to allow the operation of trains with a 400kph capability. While a train capable of this speed does not exist, one assumes that the power supply system will also be “future proofed” to allow it to supply power to run double length trains at high speeds. In order to achieve decent acceleration above 300kph, and make most use of the short sections of line that have 400kph capability, the trains would probably need 30 to 40% more power than the AGV-11, so 25MW for a 400m train, would not seem unreasonable. It would therefore appear that the catenary should be capable of supplying around ten times the power that might be needed for a 200m AGV-11 at 225kph.

    One assumes that HS2 have thought this through, come up with a solution and have factored this into their costs.

    As a footnote, the AGV-11 is used in Italy and is referred to in an Alstom brochure found here
    This shows that this particular version has a maximum commercial speed of 300kph, 5 traction units and a power of 7.6MW.


    December 19, 2014 at 11:15 pm

  2. ORR is quite scathing of NR’s (and TOCs’) performance in first 2 quarters of CP5:

    Starting CP5 having fallen behind in final year of CP4, ORR outlines where NR is playing catch-up but falling further behind. The CP5 plan depends on high quality input data on assets etc but NR is currently unable to deliver on this.

    Dft is having to fund a massive increase in NR debt requirements but has virtually no input into NR’s performance. Meanwhile, DfT claims that it is really spending big in the North even though the total major expenditure on enhancements here (over an uncertain but protracted period) is only equal to the spend on Reading infrastructure improvements, however worthwhile these no doubt are.

    All your recent posts simply demonstrate what a mess DfT and its partners are getting into and who better than our Sec of State, when in a hole, to keep on digging.


    December 20, 2014 at 11:39 am

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