High Speed Rail - Transport Committee Contents

Further written evidence from Jonathan Tyler, Passenger Transport Networks (HSR 138A)


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:

other North West1
Yorkshire and East Midlands3

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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Prepared 8 November 2011