Network Rail has secured the services of a £40 million "factory train", which will be used to speed up the electrification of the Great Western main line.
The German-built High Output Plant system (HOPS) will be used to transform 235 miles of track between Maidenhead and Swansea and will dramatically increase the efficiency of the project.
Network Rail was recently challenged by the Office of Rail Regulation to make cost efficiencies and the best way of achieving this is to use state-of-the-art technology like the HOPS on major projects.
The train - which is 23 vehicles long and has been described as a factory on wheels - will operate at night, which will enable services to run during the day.
Without it, the upgrades would have taken place at the weekends - taking far longer and causing a great deal more disruption.
Project director for Network Rail, Western and Wales Robbie Burns hopes to have electric trains running to Swansea by 2018.
"Electric trains are more reliable, cleaner, accelerate faster and use less energy. Their fuel cost is 45 per cent lower than diesel trains and they are also cheaper to maintain," he commented.