In the Cardiff City Region, work is about to start on Phase 2 of the South Wales Metro running from 2017 to 2023. This will largely focus on modernising the core Valley lines to increase the frequency of trains, reduce journey times and potentially add stations and network extensions.

In 2015 the Welsh Government committed in principle £580 million to the Metro, with the Cardiff City Region deal signed earlier this year, adding the potential to extend the scope with a capital project of over £700 million.

Transport for Wales, the Welsh Government body set up to deliver the Metro has set output-based procurement targets, with the aim being that the supply chain will innovate in determining the best way to meet the frequency and passenger carrying demands. It is considered likely that large parts of the existing heavy rail network to light, or lighter rail with the potential for on-street running in some parts.

This could certainly offer greater connectivity at a lower price than heavy rail, but possibly not as low as it could be. A criticism levelled at tram schemes in the UK is that they have overrun on cost and caused significant disruption during the construction phase. Whilst conversion of heavy to light rail should be cost effective as the tracks are already in place, there is an issue with a lack of standards and specifications for light rail, with the result that heavy rail standards are often used in their place, or with a simple calculation to reflect lower weights and forces. The result is that the track and vehicles can be over-engineered, whereas a bottom up approach with the development and adoption of sensible performance based standards reflecting actual vehicle weight and speeds could lead to cost reductions during the initial conversion phase, which would be increased further should on-street running be deployed to a great extent.

With the level of investment potentially going into light rail in South Wales, not to mention extensions to existing lines and potential new schemes elsewhere in the UK, a good return might be made from setting aside funds for research and development on performance based light rail standards. This could result in cost savings on the Metro in South Wales and future UK schemes. Another option could be to seek to cooperate with European partners, where some standards or common practices could be taken directly, or used as the basis for a UK or common European standard, and funding could be pooled to develop standards where they are missing.

The lack of standards isn’t the only reason that light rail schemes, particularly for on-street running, have proven to be expensive and disruptive. The cost and disruption of moving utilities is a major factor, but work has been and continues to be undertaken on developing prefabricated modular sections that could reduce or remove the need for diversions. Other work has been undertaken on inductive power solutions in conjunction with batteries to remove the requirement for overhead lines in certain areas, which would offer benefits in reducing street clutter, disruption during construction, or to avoid raising of bridge decks where they fall foul of gauge.

There are other areas where the potential to reduce costs and disruption could be explored such as the modular design and offsite construction of light rail stops and even stations. Not only would work on developing standards provide a return on investment for the schemes in the UK, but it would potentially offer the opportunity for UK companies to export the knowledge and experience gained to schemes worldwide in the future.

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