High Speed Rail in the UK

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High Speed Rail in the UK Powered By Docstoc


In January 2009 the Government                          The long lead times required for such projects align
                                                        with Government targets for a more sustainable
announced that it is creating an                        national energy mix; new services could by then
organisation called High Speed                          be capable of supporting maximum speeds up
Two. The company is to consider                         to 320kph (200mph) without additional carbon
                                                        penalty. However, we believe that the energy
the case for new high speed services                    targets are extremely challenging. In the event of
from london to Scotland and to                          these targets not being achieved we recommend
develop a proposal for an entirely                      that line speed should be restricted to maintain a
                                                        sensible balance between shorter journey times
new line between london and the                         and reducing emissions.
West Midlands. IMechE welcomes
this announcement and considers                         In summary, the Institution:
high speed rail a central part of                       •	 Supports the construction of High Speed Two
                                                           but believes it is only likely to deliver significant
future transport policy and climate                        carbon reductions if our electricity supply mix
change mitigation.                                         decarbonises considerably. If our energy targets
                                                           are not achieved, line speed should be limited
Encouraging modal shift should be a core tenet of          until our grid mix is sufficiently sustainable to
a more environmentally sustainable UK transport            deliver the climate change mitigation we aspire to;
policy. By reducing inter-city journey times, high      •	 Advocates a new pricing model that reviews
speed rail has the potential to provide a realistic        of the cost of tickets across all modes of travel.
alternative to other more carbon intensive modes           Ticket prices should reflect the actual carbon
of travel. However, we should be realistic about           impact of each journey and thereby incentivises
the potential carbon saving this may achieve. At           less polluting forms of travel;
speeds above 160kph (100mph), much more energy is
                                                        •	 We don’t forget our existing infrastructure.
required to overcome air resistance and so the faster
                                                           High Speed Two is decades away. In the
we go the less the environmental benefits are.
                                                           meantime, we recommend that investment should
                                                           be focussed on achieving higher average speeds
                                                           to reduce journey times on the existing network.
                                                           This is best done by smoothing out the speed
                                                           profile and removing bottlenecks rather than
                                                           developing a number of short, fast stages.

Improving the world through engineering


Rail usage has increased considerably in the UK over       •	 low emissions. Using the same loading
the past 10 years with 50% more passengers and 40%            factors, emissions from high speed rail compare
more freight1. This increase has been accommodated            favourably, particularly for journeys over 200km
by incremental improvements to the existing                   (125miles). The exceptions are conventional rail
network such as the West Coast and Thameslink                 and coach travel where emissions are marginally
upgrades. However, further growth of 22.5% and                less5. If new systems were electric, then emissions
30% for passengers and freight respectively is                attributable to rail would reduce as a more
forecast by 20142. Despite these improvements, the            sustainable and renewable national energy mix
existing network is therefore currently under severe          was introduced.
strain and this situation is only likely to get worse.
Regardless of whether we pursue high speed or not,
the UK will need more rail capacity.                                                                     Coach

Our existing network is far behind many of our
European counterparts. With one or two exceptions                                                Rail – Electric
such as the West Coast and Great Western lines,
                                                         Transport mode

UK passenger services are limited by maximum
track speeds of 160kph. Despite this, many of our                                                  Rail – Diesel
newer trains are capable of speeds up to 200kph
(125mph). The upgrading of other key inter-city
lines would go a long way in reducing times and                                               Rail – High Speed
accommodating any significant passenger growth.
Put simply, our technology is being restricted by
our existing network.                                                                                        Car


                                                                          0   50        100      150        200    250

                                                                                   grams per passenger km
                                                           Figure 1: Average CO 2 emissions by transport mode
                                                           Source: WS Atkins, “Because Transport
                                                           Matters – High Speed Rail” 2007
                                                           •	 Direct city centre access. London to Glasgow by
 In late 2008, the Government established a                   conventional rail takes five and half hours point
 National Networks Strategy Group and announced               to point. By air, typical journey times, including
 an acceleration of work to develop a sustainable             check-in, security screen and city centre transfers,
 transport system, including high speed rail.                 are three and three quarter hours. Whole journey
 Indeed, in January 2009 the Government                       times by high speed rail could be as low as two
 announced High Speed Two, a company                          and three quarter hours – far quicker than air
 established to look into high speed rail in the UK.          travel and car or coach6.
 But we are already much of Europe and the rest
 of the developed world. Japan led with the bullet         •	 High frequency of departures. Cab-based
 train in 1964 with most large industrial countries           signalling on high speed trains will allow a higher
 following suit. There are now 3,480 miles of                 frequency of service whilst maintaining safety.
 high speed lines in France, Germany, Belgium                 Trains will “know” the position and speed of
 and Spain with a further 2,160 miles under                   trains in front of them and thus will not require
 construction and another 5,280 miles planned.                the current 7½ mile gaps between services.
 China, Taiwan and Korea also have high speed              •	 Extra capacity for both passenger and freight.
 systems and one is about to be constructed in the            This would allow extra rail services by releasing
 United States. The UK has just 70 miles of high              capacity on existing lines and help ease crowding
 speed rail3.                                                 on inter-urban rail journeys. This will not only
                                                              increase passenger capacity but also have potential
 High Speed Rail in the UK is not a new concept. In           freight benefits. However, a high speed line would
 2001 a study by WS Atkins4 examined options for              not alleviate the gauge problems experienced by
 improving existing East and West coast routes to             freight operators on the current network.
 the North, based on the high speed technologies           •	 Improved links to key international gateways.
 used in France. The MAGLEV contactless power                 Any new high speed line should only be considered
 transfer system was also considered but with                 if it were to be linked to our existing international
 issues such as lack of compatibility with other              gateways, including Heathrow and St Pancras.
 high speed lines, sustainability, cost and the fact
 that it is still in the development stages, was not
 considered to be a viable alternative. The study
 presented its recommendations in 2003, concluding
 that there was a strong business and transport
 case for a range of high speed rail options.
THE DISADvANTAGES oF HIGH SPEED                               The faster a train moves the more energy it requires.
                                                              As Table 1 shows, energy consumption increases
•	 Price. Inter-city rail prices do not compare               with speed and the performance of a train running at
   favourably with low cost airfares particularly on          300kph (186 mph) uses more than twice the amount
   routes such as London – Edinburgh or Glasgow               of energy than a train travelling at 200kph, with only
   with airline costs going down and rail costs rising7.      a resultant 50% increase in speed. Indeed, to achieve
                                                              450 kph (280 mph), a train would require 5 times
•	 limited routes. Road and air transport tend to             more energy than an equivalent running at 200 kph.
   better link multiple routes, whereas high speed
   links tend to only link a small number of cities in a      However even at the higher speeds the there is
   linear fashion.                                            considerable environmental gain over other forms
•	 Rolling resistance. At 200kph 70% of the energy            of transport. As total journey time is an important
   required is used in overcoming wind resistance.            factor for passengers there is a strong case for
   This factor goes up with the square of the speed           selecting a speed that competes with air travel and
   and is over 90% at 350kph (220mph). Put simply,            accepting the higher energy use. The Rail Safety and
   the faster you go the more energy you need.                Standards Board estimates that using the 200kph
•	 Possibility of no net emission reduction. There            model a saving of up to 140 gCO2/passenger/km
   is a risk that the introduction of high speed rail         could be made for each passenger switching from air
   may stimulate demand for travel and therefore              to high speed rail9.
   generate additional emissions. People may decide
                                                                             3.5                                           70
   that longer distance commuting is more feasible
   and any move from conventional rail to high speed                                                                                                           Speed v Time
   would increase emissions. Further, the emissions

                                                                                                                                 Energy consumption kWh/seat
                                                                                                  Speed v Time
   benefit of high speed is entirely dependent our
   electricity mix (power/weight ratios mean that                            3.0                                           60
   electric power is a practical requirement for speeds
                                                            Journey time h

   over 200kph). Currently, the UK’s centralised
   generation capacity is very carbon intensive.
                                                                             2.5                                           50


Currently the Department for Transport defines
                                                                             2.0                                           40
high speed as over 240 kph (150 mph)8. In general,                                                Speed v Energy
UK passenger services operate at a maximum speed
of 160 kph with a mix of diesel and electric power
with inter-city services on the West Coast mainline
capable of 200kph. Examples of modern high speed                             1.5                                           30
                                                                                   200    250         300          350
trains operated in Japan and Europe can travel at
over 320kph, although average speeds tend to be                                           Speed limit km/h
less. If we were to undertake building a high speed           Figure 2: Relationship between Energy, Speed and Time
line, how fast should we go?
                                                              Running trains at 320kph would be no problem if the
There are those that argue we should go as fast as we         energy used was from a sustainable and renewable
can. However, is this sensible? Indeed, Maglev has            source. However, UK energy supply is anything
been touted, which currently runs at speeds of up to          but. Indeed, the carbon footprint of the national
430 kph (268 mph) in Shanghai. Maglev should not be           electricity grid has actually risen in recent years to
considered not only because of the cost but because it        562gCO2/KWh in 200610. Unless we significantly
would require a completely new railway system that            decarbonise our electricity supply, the environmental
would not be compatible with existing infrastructure.         benefits of high speed are almost nonexistent.
A balance between speed – and therefore journey               Fortunately, infrastructure development on such a
time – and emissions has to be found.                         large scale takes a number of years.

  Speed (kph)                                     160      200                      225     270         300         330          450
  Speed (mph, rounded)                            100      125                      140     168         186         205          280
  Energy Consumption                             0.64        1                     1.27    1.82        2.25         2.72        5.06

Table 1: Energy and power use coefficients for
different speeds, compared to 200 kph
CoNCluSIoN                                               REFERENCES
                                                              Transport Statistics Great Britain 2008
•	 The Institution supports the construction of          2
                                                              DfT, Delivering a Sustainable Railway, July 2007
   High Speed Two but believes it is only likely         3
   to deliver significant carbon reductions if our            DfT Britain’s Transport Structure –
                                                              High Speed Two, January 2009
   electricity supply mix decarbonises considerably.     4
                                                              Atkins “Because Transport Matters – High Speed Rail” 2007
   We consider that new services should be capable       5
   of supporting speeds up to 320 kph (averaging              EU Study – Competition between air and
                                                              High Speed Rail, November 2007
   200–240kph). The timescale for infrastructure         6
   development is such that the UK’s sustainable         7
   energy mix should have improved sufficiently          8
   by then to allow these higher speeds without               DfT Britain’s Transport Structure –
                                                              High Speed Two, January 2009
   additional emissions. If our energy targets are       9
                                                              RSSB Report “The case for rail 2007. The first
   not achieved, line speed should be limited until           sustainable development review of the mainline
   our grid mix is sufficiently ‘green’ to deliver the        railways of Great Britain” 25/06/07
   climate change mitigation we aspire to;               10
                                                              DEFRA carbon emissions reporting guidelines –
•	 However high speed should be accompanied                   electricity conversion factors.
   by a new ticketing model that reviews of the
   cost of travel across all modes of travel. Ticket
   prices should reflect the actual carbon impact
   of each journey and thereby incentivise less
   polluting forms of travel;
•	 But we mustn’t forget our existing
   infrastructure. High Speed Two is decades away.
   In the meantime, we recommend that investment
   should be focussed on achieving higher average
   speeds to reduce journey times on the existing
   network. This is best done by smoothing out the
   speed profile and removing bottlenecks rather
   than developing a number of short, fast stages.

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Mechanical Engineers

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