The Year 2 report described a number of possible fitment scenarios in terms of the timing of implementation on the high speed lines, and summarised plans for implementation over the remainder of the network. The scenarios were supported by route-by-route analysis at an outline level.

This analysis was built on Network Rail?s June 2003 10-Year Resignalling Programme (v.2). The central option at that stage was ?Scenario A2?, an aggressive rollout of ERTMS Level 2 without line-side signals, targeted at completion of high speed lines by 2015. The report noted that this option, although having a good long-term business case, was of high deliverability risk, and required significant upfront investment in the order of £1.5 billion over the first 10 years.

Over the past 12 months, the following changes to the economics and practicability of national implementation have become evident:
* The predicted safety benefits of the Train Protection and Warning System (TPWS) have been reconfirmed by in-service experience over the period;
* There has been little if any reduction in capital costs of ERTMS equipment quoted by suppliers, either in the UK or elsewhere in Europe;
* The long-term benefits of ERTMS in infrastructure cost reduction and network performance improvement have been revised and validated, but these only apply when ERTMS is fitted as part of signalling renewals and is used to eliminate line-side signals, thus requiring all trains on a route to be fitted;
* The reliability of the network is increasing, and it has become clear that the regulatory targets for network performance are likely to be met without a contribution from ERTMS. Thus the prospective performance benefit from ERTMS is reduced owing to this improvement in the performance base;
* It has become clear that ERTMS development in Europe is not proceeding as fast as hoped and is some way from being able to support complex mixed traffic railways. Consolidation of the ERTMS specification has been further delayed and reliability problems are reported in some of the current commercial projects; and
* Network Rail has developed a new and more practical approach to migrating conventional signalling to ERTMS, developed as part of their expanding involvement in the Programme.

The NEP team is revising the national implementation strategy to take account of these factors. The aim of this work has therefore been to produce implementation plans that:
* Through synergies with infrastructure and train renewal, minimise the costs of fitment and maximise the longterm benefit;
* Are, by their relationship with the Network Rail resignalling programme, demonstrably deliverable;
* Are built on the lessons of recent major projects in the UK rail, in terms of the effective separation out of discrete and tractable elements of work; and
* Recognise Health and Safety Commission (HSC) concerns that delivery of ERTMS (as a means of providing ATP on UK high speed lines) should, in terms of compliance with the Joint Inquiry findings, take place at an early date.

These objectives can best be approached by adopting a natural implementation strategy, where ERTMS Level 2 System D is fitted as part of signalling renewal, and retrofitting trains is avoided as far as possible by waiting for the opportunity to fit as part of new train procurement.

The new national implementation plan has been labelled the ?natural? implementation plan, because implementation is projected as infrastructure and trains are due for renewal.

In parallel, an implementation plan has also been developed that could deliver ATP on the UK high speed lines by 2025.

This strategy requires early resignalling of several sections of the East Coast Main Line (ECML) in addition to overlaying ERTMS on the recently resignalled sections of the West Coast Main Line (WCML). Hence, this prioritised implementation plan will require significantly more upfront investment and represents a higher risk when compared to the natural implementation plan.

5.3.1 Natural implementation plan

The natural implementation plan represented in Figure 5 is aligned with Network Rail?s resignalling and GSM-R plans and integrated with DfT/SRA franchising and national rolling stock renewals strategies, in their current state.

The natural implementation plan, by its nature, proposes a slower rollout of ERTMS than envisaged by Uff-Cullen or by the indicative industry plans documented in previous end of year reports. The spread of implementation dates over time show broadly how the high speed line implementation could proceed. The first major scheme is for the ECML, which remains the priority for ATP implementation, since the Great Western Main Line (GWML) already has ATP and West Coast has recently been resignalled to modern standards, which include the ?robust train protection measures? introduced by Network Rail.

This plan is still being refined in preparation for submissions to the DfT and the ORR, in line with the regulatory Signalling Review process. It will remain indicative until these reviews have confirmed in detail the funding needs for signalling, including ERTMS, over the period 2009 to 2014, and the
overall long-term signalling strategy has been confirmed by the Government. However, the development phase funding already available is sufficient to carry forward all the key activities necessary to support the Programme up to 2009.

The original target completion of high speed line fitment by 2015 is no longer considered feasible by the industry. Over the past year, experience in Europe has underlined the scale of programme risk implicit in the rollout over a mixed traffic network, and projected costs remain high. The prioritised implementation plan described earlier, which delivers ATP on the UK high speed lines by 2025, is still under evaluation.

The natural and prioritised implementation plans are based on the ?steady-state railway?. There will clearly be an interaction with any major modifications or upgrades to the network. Both Thameslink 2000 and Crossrail major projects have prospective timescales in the early years of the implementation programme, and would potentially change the ERTMS implementation sequence as well as adding material schedule and volume pressure. However ERTMS also represents a potential benefit for both projects.

Its performance and capacity characteristics should be well suited in principle to the high-capacity nature of Thameslink 2000 and Crossrail, but cannot be considered as proven technology in this context. Crossrail, in particular, which is considering Automatic Train Operation within its core option, needs special consideration.