Annex 2: Capacity calculations
Briefing note on capacity issues by Richard Goldson
and Bob Linnard, Specialist Advisers to the Transport Committee,
October 2011.
West Coast Mainline - Supply and Demand
1. A key reason cited by the Government for building
HS2 is the extra passenger and track capacity it would provide.
Some critics argue that upgrading the existing WCML would provide
sufficient capacity for the foreseeable future. This note examines
the supply of extra capacity under different options and the demand
for capacity (the latter based on information provided by DfT
and HS2 Ltd).[343]
Supply
2. The table below summarises the extra capacity
that would be provided on WCML under three options - HS2 London-Birmingham,
the conventional upgrade modelled by DfT (Rail Package 2 - RP2)
and the variant to that proposed by 51m.[344]
It also shows the percentage capacity increases relative to the
HS2 reference case date (2008).
3. It shows that the recent upgrade and high-frequency
timetable have already increased capacity from 90,000 seats per
day in 2008 to 120,000 seats in 2011.
4. The RP2 and 51m proposals would both increase
that 2011 figure by a further 80% to 90% to around 220,000 seats.
Either could probably be implemented by 2016. Both these proposals
would provide a rather smaller increase in the seats available
in the peak - around 60% (relative to 2011) in the case of 51m.
5. HS2 would provide significantly more additional
capacity than RP2 or 51m. It would increase the daily capacity
(relative to 2011) by some 145% to nearly 300,000 seats, and the
peak capacity by a similar percentage, albeit not until 2026.
Demand
6. HS2 Ltd has provided information on current and
forecast long-distance (100 miles and more) trips on WCML, though
only on the franchise currently operated by Virgin.[345]
That proviso means that the figures for demand are not directly
comparable with those above for supply. The important thing is
the relative rate at which supply and demand increase.
7. In 2008 there were 50,000 long-distance trips
per day over the southern end of Virgin West Coast. By 2011 this
had risen to about 65,000. DfT's standard model for forecasting
rail passenger demand shows growth of 2% per year, well below
the 10% per year actual growth from 2008 to 2011 on WCML. This
means that the forecast of 57,000 trips by 2021 has already been
exceeded. Similarly, it means that the forecast of 101,000 trips
by 2043 - about 50% more than today - is probably too low.
8. But if the model is right and demand quickly drops
back to 2% per year, then RP2 or 51m would provide enough capacity
for perhaps 20 years, at least on an all-day basis.
9. HS2 Ltd says that HS2 would of itself increase
demand - by an extra 37%.
Load Factors
10. The load factor is the rail industry measure
of crowding. A load factor of 100% means that all seats are occupied.
(If the journey is less than 20 minutes it would also assume standing
within the design limits of the rolling stock.)
11. DfT's figures show load factors on Virgin West
Coast between London and the West Midlands (the busiest stretch)
at 56% in 2008, dropping to 42% in 2021. That reduction reflects
the extra capacity created by the recent upgrade running ahead
of the 2% per year modelled demand growth. But as with the demand
figures in paragraph 8 above, the 2021 forecast does not
reflect the actual 2008-11 surge in demand.
12. By 2043, without HS2 or any alternative, the
load factor is forecast to have risen to 76%. That reflects a
forecast doubling of 2008 demand. But RP2 or 51m would broadly
double today's supply of capacity. So why might we need the much
bigger increase in capacity offered by HS2 (which, even allowing
for the 37% increase in demand that the new line would generate,
would by 2026 give a much lower average load factor than any alternative)?
The answer lies in the way demand is concentrated at peak periods.
Peak Demand
13. DfT/HS2 Ltd acknowledge two limitations in their
figures. First, as noted, they ignore the actual demand growth
over the past 3 years. Second, the load factors are all day
averages which will mask much higher demand in the morning
and evening peaks. The question of whether these peaks can be
spread is crucial.
14. The McNulty report on rail value for money urges
a move from predict and provide to predict, manage and provide,
i.e. using different pricing structures to make better use of
capacity. DfT have largely dismissed the scope for this on WCML,
arguing that 9-5 commuting is here to stay for the foreseeable
future.[346] If they
are right then even a (probably understated) 76% all-day average
load factor would lead to unacceptable peak crowding, reinforcing
the case for the step change in capacity provided by HS2.
15. As an aside, if DfT are right that demand cannot
be spread and the 10% annual growth of the past three years
were to continue, even pressing ahead with HS2 would mean severe
overcrowding for commuters post-2020, given that HS2 cannot be
in operation before 2026.
Conclusions
16. HS2 is needed for capacity reasons if the growth
of the last 3 years continues or if peak demand cannot
be spread.
17. If the growth rate were to fall back quickly
to 2% per year (or less) RP2 or 51m would suffice, but only if
an answer could be found to the problem of peak demand.
Table 1
| Interventions |
Daily Trains | Daily Standard Class Seats
(Increase over 2008 Base)
| Daily Seats (Std + 1st)
( Increase over 2008 Base)
| Peak Standard Seats (one hour, one way)
( Increase over 2008 Base)
| Peak Seats Std + 1st (One hour, one way)
( Increase over 2008 Base)
| Comments |
| Train investment with no/little infrastructure investment
| | | |
| | |
| HS2 2008 Base (Reference case)
| | 59,298
| 90,000 | 2,289
| 3,482 | Gross figure obtained from HS2 Strategic Alternatives Study. Peak hour figures estimated.
|
| Current timetable | 286
| 81,924
(38%)
| 120,244
(34%)
| 3,162
(38%)
| 4,652
(34%)
| Includes Voyager services (30 daily).
|
| Evergreen 3 (2011 Chilterns line upgrade)
| [68] | [28,900]
[55%]
| [28,900]
[32%]
| | | Committed scheme, complete in 2011, but excluded by 51m and here as it is unclear how much of the capacity is actually available to WM passengers after allowing for intermediate usage to Bucks, Oxon and Warks.
|
| Committed train lengthening project
| 286 | 105,924
(79%)
| 144,244
(60%)
| 4,102
(79%)
| 5,592
(61%)
| Committed scheme - implemented from 2012.
|
| December 2013 additional services
| 306 | 113,679
(92%)
| 154,899
(72%)
| 4,102
(79%)
| 5,592
(61%)
| Additional hourly off-peak train each way. Note off-peak only.
|
| First class reconfiguration as proposed by 51m
| 306 | 134,379
(127%)
| 162,903
(81%)
| 4,630
(102%)
| 5,620
(61%)
| One car converted from first to standard class.
|
| 12 car sets as proposed by 51m (except Liverpool)
| 306 | 166,908
(181%)
| 195,432
(117%)
| 5,810
(154%)
| 6,800
(95%)
| Major physical constraints at Liverpool.
|
| Infrastructure investment, proposed by 51m to relieve pinchpoints
| | | |
| | |
| 30 additional services enabled
| 336 | 186,648
(215%)
| 218,538
(143%)
| 6,391
(179%)
| 7,480
(115%)
| |
| Total envisaged by 51m
| 336 | 186,648
(215%)
| 218,538
(143%)
| 6,391
(179%)
| 7,480
(115%)
| |
| Increase over Current |
50 | 104,724
(128%)
| 98,294
(82%)
| 3,229
(102%)
| 2,828
(61%)
| |
| RP2 |
| | 224,600
(150%)
| | | Estimated from Strategic Alternatives Paper and calculations re Evergreen
|
| RP2 Increase over Current
| | | 104,366
(87%)
| | | |
| HS2 (West Mids) Proposal
(All New Capacity)
| 336 |
| 174,900
(194% over base)
(145% over current)
| | 7,150
(205% over base)
(154% over current)
| Assumes 15 hour day with 3 hour peaks; all trains 550 capacity, except 50% of Birminghams will be 1100
|
| HS2+Y Proposal (West Mids & NW only)
(All New Capacity)
| 312 |
| 184,800 |
| 8,800 | Assumes 15 hour day with 3 hour peaks; all trains 550 capacity, except 50% of Manchesters and Birminghams will be 1100
|
| HS2+Y Proposal (All destinations)
(All New Capacity)
| 492 |
| 283,800 |
| 12,100 | Assumes 15 hour day with 3 hour peaks; all trains 550 capacity, except 50% of Manchesters and Birminghams will be 1100
|
343 Ev 267 Back
344
Ev 154 Back
345
Ev 267 Back
346
Ev 254 Back
|
