Transport for Wales (TfW) has kicked off the race for construction, engineering and design firms to bid for contracts in its £700 million development and maintenance programme.
Its Sustainable Transport Infrastructure Delivery Framework will run over the next two years and a bidders day is to be held on February 13th to find the contractors.
Key elements of the scheme may include the South Wales Metro, as well as enhancements to the railways around the borders with England and multi-modal transport interchanges.
The South Wales Metro is designed to be a system for the urban areas covering Cardiff, Newport and Swansea plus the valleys that will provide better integration of services and ticketing operations. Designed to boost economic development and shorten travel times, it will also provide more capacity for travellers.
TfW states: "The South Wales Metro is an ambitious project linking people and jobs across South East Wales in a fast, efficient and environmentally positive way."
As well as heavy rail and buses, the Welsh government has envisaged a new light rail system that will integrate with the existing bus and rail stations. Travellers would be able to switch between train and light rail services in the same way London commuters can hop off a train and onto the Tube.
The Wales and Borders service will focus on a key cross-border element of rail travel for Welsh commuters. It is impossible to get from places like Cardiff and Newport in the south to the larger north Wales towns such as Wrexham without passing through England.
TfW describes the aim of the project as being "to create a rail service that benefits the whole of Wales, as well as communities along the border in England". Its work will include enhancing stations and also improving the core valley lines that form part of the South Wales Metro network.
A light rail or tram system would be the first of its kind in Wales, with existing systems now in place in Manchester, Sheffield, the West Midlands, Nottingham, south London and Edinburgh.