Further written evidence from Jonathan
Tyler, Passenger Transport Networks (HSR 138A)
THE MAXIMUM
CAPACITY OF
HS2 AND THE
PRIORITIES FOR
ITS USE
In written evidence to the Commons Select Committee
Inquiry into High Speed Rail [HSR 138] I drew attention to the
confusion surrounding the capacity and timetabling of HS2. Having
listened to the session of oral evidence on 21 June and checked
the (uncorrected) transcript I am alarmed at how unappreciated
this fundamental issue is. It urgently needs rigorous examination.
Several witnesses before the Committee quite rightly
emphasised their concern that the plans for HS2 both lack a strategic
context and are not based on any substantive timetable planning.
This is nowhere more apparent than in the rather loose expressions
of aspirations for services. And if those cannot be realised then
the business case will be undermined.
The maximum number of trains/hour on any high-speed
railway is 14 (into Tokyo in the morning peak on the original
Tokaido Line). I note the categoric statement of Pierre Messulam
from SNCF [Q84] that the maximum feasible capacity of a high-speed
railway is 16 trains per hour. No one has persuasively demonstrated
that that can be exceeded, which makes HS2 Ltd's assumption of
18 seem exceptionally optimistic.
In order to relieve the capacity shortfall on the
West Coast Main Line (accepting here that a shortfall will exist
and that a new railway is the appropriate solution) the minimum
requirement for London paths in a peak hour on the "Y"
network is as follows:
| Scotland | 1
|
| Manchester | 3 |
| Liverpool | 1 |
| other North West | 1 |
| Yorkshire and East Midlands | 3
|
| Birmingham | 3 |
These numbers are based on current patterns, likely growth and
reasonable aspirations. They also represent frequencies that would
be credible in market terms and broadly adequate relative to the
construction costs of a high-speed line.
The total number of paths is 12. However, HS2 Ltd envisages four
Birmingham trains/hour in the peak, while the draft WCML Route
Utilisation Strategy raised the foreseeable need for four Manchester
trains. It is improbable that there would not be similar requirements
on the other routes, and only three per hour on the eastern arm
of the "Y" is a bare minimum that would diminish any
hope of significant relief of the East Coast and Midland Main
Lines.
This leads to the inescapable conclusion that the maximum capacity
of 16 trains per hour will be fully utilised by London services.
It follows, given present assumptions, that no capacity will be
available for independent through services to HS1, the Channel
Tunnel and Europe, or for direct services to Heathrow Airport.
For each of these routes the minimum pattern to provide attractive
options for travellers and to justify the (high) cost of construction
of the links would be two trains per hour. Four paths could
be taken from the London totals outlined above, but only if the
HS2 and classic timetables for the routes concerned were to be
integrated more intimately than has so far been suggested in order
to offer an excellent overall service, albeit with many connections
rather than through trains. This solution would however become
increasingly difficult if the HS1 and Heathrow frequencies were
raised to the more desirable 3/hour each and infeasible for any
greater number.
An alternative approach would be to adopt "portion working",
ie to run trains coupled together over the common and busiest
sections. Since the line will be engineered to take 2 x 200m trains
and since it will optimise the technical arrangements for (un)coupling
its practicability is not in question. However the many issues
that would need resolution do not appear to have been addressed:
— locations
for (un)coupling must be identified and designed (and may not
lie on HS2 itself);
— the
best combinations of services must be carefully considered;
— even
with optimal operational arrangements (un)coupling takes time;
— portion
working can transfer disruption from one section to the wider
network; and
— interaction
between HS1 and HS2, in planning and in real time, will be problematic
(it could for example cause a reduction in paths/hour in order
to allow for operational delays).
In sum, portion working might help to resolve
the conundrum of how HS2 can serve the London market and
the Europe market and the Heathrow market, but this can
only be established if the present specifications are revisited
and if a comprehensive strategic-timetabling and infrastructure-planning
exercise is undertaken. Even then it is difficult to see how the
more optimistic forecasts of demand for all three markets are
compatible with a two-track railway limited to 16 trains per hour.
There is potentially a similar incompatibility between
the aspirations for inter-regional (non-London) services on the
two arms of the "Y" and the capacity of the route between
their junction near Lichfield and the delta junction at Water
Orton.
Finally it must be stressed that this assessment
assumes strong central planning of the utilisation of capacity,
albeit with delivery possibly in the hands of more than one operator.
If on-track competition between operators were to be introduced
(as is now envisaged on HS1 and assumed in certain quarters for
HS2) then the matter of priorities would become even more intractable.
Jonathan Tyler designed what is to date the only
integrated timetable for HS2 and WCML. This was commissioned by
Greengauge 21 ** and was the work referred to by Professor Nash
in his evidence on 21 June [Q21].
** see http://www.greengauge21.net/publications/capturing-the-benefits-of-hs2-on-existing-lines/
25 June 2011
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