Maybe Tram-Trains aren't such a good idea for the valleys.
NAO: The Sheffield to Rotherham tram-train project: investigation into the modification of the national rail network
https://www.nao.org.uk/press-release/the-sheffield-to-rotherham-tram-train-project-investigation-into-the-modification-of-the-national-rail-network/
I can well imagine an NAO/Auditor General For Wales report saying similar things about the South Wales Metro in a few years.
NAO: The Sheffield to Rotherham tram-train project: investigation into the modification of the national rail network
https://www.nao.org.uk/press-release/the-sheffield-to-rotherham-tram-train-project-investigation-into-the-modification-of-the-national-rail-network/
In May 2012, when Ministers approved the programme, the Department expected Network Rails modification of the national rail network to cost £18.7 million and the tram-train scheme to be completed by December 2015. By December 2016, the cost of these works had quadrupled to £75.1 million and Network Rails project is now expected to be completed in May 2018.
Network Rail established that works were more complex than it anticipated at the design stage, that it had incurred additional costs in dealing with the condition of assets and the technical innovations required more time than originally expected. At the start of the project, Network Rail did not have a full understanding of the costs, and revised its forecasts as it identified the technical challenges involved in testing the technology.
I can well imagine an NAO/Auditor General For Wales report saying similar things about the South Wales Metro in a few years.