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INFORMED SOURCES August 2005

Gauging policy expands options

A 26m successor to the Mk3? Engineering common sense is being applied to gauging.

On 24 June the Strategic Rail Authority handed over what could be its most enduring legacy – a new gauging policy for the rail network. Publication of the policy follows over a year of collaborative work between the SRA and the Vehicle/Structures - Systems Interface Committee (V/S-SIC).

Systems Interface Committees (SIC) emerged from the Wheel Rail Interface and TPWS Systems Authorities when the liabilities implied in the word ‘Authority' made insurance for the members prohibitively expensive. Instead of the two ad hoc authorities, the six SICs have been structured to cover all the interfaces.

While covering all interfaces, there was concern that the lack of ‘Authority', could make the Committees ineffective. But, there are various forms of authority and what the SICs may have lost in terms of formal power appears to have been more than offset by the personal authority of the chairmen and committee members.

Tested

Back in March, that authority was tested when the six SIC Chairmen wrote to the SRA urging that HST2 procurement should not be rushed (Informed Sources May 2005). They warned that if the technical specification, including the many interfaces was not established before tenders were invited, capital and whole life costs could be 10% above those of an optimised designed.

SRA rejected this advice. With HST2 procurement already at an advanced stage, revisiting the technical specification would introduce unnecessary delay. The SIC chairmen were told to get with the programme.

But now listen to Transport Secretary Alistair Darling three months later. Describing IC125 as ‘one of the great success stories of the British railway' he told the Railway Forum annual conference ‘I am determined that their successor should meet the same high standards', adding, ‘We need to get it right - to properly scope and test the new design, so that it can be introduced smoothly and without causing any drop in reliability'.

And his support for the SIC Chairmen's message could not have been clearer. ‘We need to ensure that we consider how all aspects of the system work together - not buy a train without any consideration of how it operates on the track'.

Passenger gauges

In the post-SRA world, responsibility for implementing the new gauging policy will pass to V/S-SIC. The policy will be ‘facilitated' across industry by the Rail Safety & Standards Board.

For passenger trains, the policy establishes four categories of gauge. The first applies to the high speed lines covered by the European Community's High Speed Directive.

Britain has obtained a permanent derogation from standard European gauging principles. Perhaps because the Europeans don't have to squeeze modern trains through tunnels built by financially challenged early Victorian contractors, their gauging principals lack our sophistication.

Or, as the V/-SIC put it ‘International Union of Railways (UIC) gauging rules are relatively crude and make no explicit assessment of the actual clearance between a given vehicle and a line side structure'. Nor do they require any knowledge of a specific vehicle's dynamic behaviour.

Attempting to apply such conservative gauging rules to the UK network would result in only ‘unfeasibly small trains' being allowed to operate. Hence the permanent derogation with UK Issue 2 allowing Eurostar-sized vehicles to run on the UK TENs routes, namely CTRL, the East and West Coast main lines and the Great Western main line.

Much more exciting is the new Intercity gauge, or as V/S-SIC calls it ‘a gauge for a replacement for the intercity high speed train'. This gauge will be defined by the infrastructure on the TENs lines plus other principal intercity routes where the trains might run. ‘Being defined by the infrastructure' might sound restrictive, but read on. .

Four categories of route were used to define the new gauge. Category 1 obviously covers the TENs and other principle Intercity routes. Category 2 illustrates V/S-SIC's forward policy. These are routes, which would only be excluded from the Intercity gauge if they introduced major constraints or required expensive gauge enhancements.

Category 3 are routes which would be nice-to-have, but only if any gauge enhancement was inexpensive or paid for by a third party.

Also contributing to the study are diversionary routes over which Intercity gauge trains could run at reduced speed or under other operational constraints. Slow or relief lines on all multiple track section are assumed to be suitable for diversionary running

Something to note is that not one route in the three categories has ‘disproportionately affected' the size of the Intercity gauge. This means that HST2 is going to have the wide route availability of its predecessor.

26 metre

But, even better, HST2 will, thanks to the detailed knowledge of Network Rail's National Gauging Programme, be able to exploit a larger vehicle than even the Mk 3.

One of the missed opportunities of the 1980s was InterCity Director John Prideaux's vision of 26m long vehicles for IC225. He hoped Metro-Cammell would take up the option: sadly contracts with British Rail Procurement rewarded conservatism.

But now the Prideaux challenge has been taken up by ATOC Engineering Director Rebeka Sellick , a member of the V/S-SIC. All that gauging work by Laser Rail means, according to Rebeka, that when the Intercity gauge is available by Christmas it should accommodate a vehicle not only 26m long but also slightly wider than the existing Mk 3.

There is a further potential benefit from the new Intercity gauge. Experienced traction and rolling stock engineers ‘know', but can't prove, that the Mk 3 could run safely over many routes off the formal Intercity network.

Once upon a time clearance would have been checked by putting blue expanded plastic foam pads on gauge limiting bits of a vehicle and then towing it over the proposed route to see if anything rubs. Today, as David Johnson of Laser-rail puts it with a grin, the blue expanded plastic blocks are in his company's software.

At which point it is worth mentioning that Laser-rail has carried out the gauging work behind the policy free of charge and retains the IPR for the computer systems involved. According to David ‘Our purpose is to stimulate a new way of doing things – checking all options rather than selecting one or two based upon preconceptions which may not be valid'.

And there are clear benefits for existing vehicle owners and would-be operators, because the new Intercity gauge will simplify clearance for cascades. All those Mk 3 coaches currently off lease, could be cleared to run on new routes relatively quickly.

Go anywhere

And the good news keeps on coming. The aim is to define two other gauges, called ‘go anywhere' and suburban'.

Preliminary analysis suggests that the only current ‘go-anywhere' vehicle is the Class 150. But the work behind the policy has come up with three propositions.

First, many parts of the network could accept wider and taller vehicles. In addition to the Intercity routes, 26m long vehicles could operate ‘on significant parts of the network'. Finally they may be scope to increase route clearance for Class 165 diesel multiple units ‘significantly'.

Why Class 165s? They were intended for Thames and Chiltern services which run over former Great Western Railway broad gauge routes. BR, unconstrained by residual value, exploited the additional width.

With computerised gauging you move from a half empty glass to one that is half full. Once you are able to identify the worst pinch points which have the greatest effect on the vehicle gauge a route can accept you can, given the will, the time and the money, do something about it.

With gauge enhancement, once you remove the major show stopper, the gauge is defined by those restrictions which are less expensive to remove. And the cost of removal can be partially offset against the additional expense of acquiring non-standard route specific rolling stock when train fleets are replaced.

Longer term, the ECML provides a lesson for today.

At the northern end of the route, civil engineering policy was that if structures had to be replaced or rebuilt, provision would be made for the additional clearances needed for eventual overhead line electrification. Extra cost was minimal, but when electrification happened, this act of faith meant that the cost of increasing clearances was also minimised.

Similarly with gauging. If you define the ‘go-anywhere' gauge on the basis of the incremental removal of the limiting structures, as these are replaced, they are rebuilt to the new gauge.

This incremental approach to ‘go-anywhere' will identify what V/S-SIC calls ‘clusters' of restrictions. If these are removed, it may be possible to introduce a ‘suburban' gauge, between Intercity and ‘go-anywhere' which would apply to the major metropolitan areas.

Of course, this is all very exciting and a welcome change from this column's endless financial analyses. The only snag is that the new policy requires long term commitment to relatively low levels of expenditure.

Getting support from DfT could be difficult, although it aligns with the current emphasis on capacity. How gauging policy will be handled in the High Level Output Specification (HLOS) for the five years from April 2009 is an unknown.

Fortunately both Network Rail and the Office of Rail Regulation are represented on V/S-SIC. When it comes to matching the HLOS to the money is prepared to pay, it will be between these two bodies. I feel a new crusade coming on.

Continues.........