Part of London's oldest train station is set to be rebuilt in Aberystwyth as part of a £10m plan for a narrow gauge railway museum.
Sections of London Bridge station's roof have been given to Vale of Rheidol Railway which operates small steam trains for tourists in mid Wales.
London Bridge station, which opened in 1836 and is used by 55 million people, is undergoing a £6bn redevelopment.
Network Rail has saved 16 columns, 14 beams and other elements of the roof.
These parts of the Grade II-listed structure will form the cornerstone of the planned new locomotive museum in Aberystwyth.
Robert Gambrill from the Vale of Rheidol Railway said it would be used to display a unique collection of narrow gauge artefacts.
"The roof offers an opportunity to show the locomotives in context within a train-shed environment and the Vale of Rheidol will work hard to recreate the atmosphere, which only a London terminus can provide," he said.
"Years ago they sold London Bridge to Arizona and now they've given London Bridge station to Aberystwyth."
Mr Gambrill said it had taken a year to arrange a deal to remove about a third of London Bridge station's old barrel arch roof.
All of the beams and columns had to be removed by cranes at night and at weekends, with specialist equipment needed to excavate the columns from their base plates after 150 years.
Mr Gambrill said there had been doubts initially whether enough of the beams and columns could be saved to enable the museum to be built.
"It has been a pleasure to work with such a dedicated team from Network Rail - their care and attention to detail has ensured as much of the structure that we need has been saved," he said.
"Without their co-operation none of this would have been possible. We all look forward to unlocking the potential of our collection and seeing the Vale of Rheidol becoming a world class tourist attraction for Wales."
Chris Drabble of Network Rail said the teams who worked on the project could be proud of what they had achieved.
"This great news has been possible because many people, from many organisations have been working together," he added.
"Up until the actual structures were lifted, we were never sure if any of this would be technically possible, so all of the teams can be really proud of what they have achieved."
The Vale of Rheidol intends to submit plans for a 100,000 sq ft (9,300 sq m) museum to Ceredigion council and also plans to apply for grants to fund the project.
The railway said it had a "unique historic collection" of around 30 locomotives and rolling stock, much of which was built in the UK and had never been displayed in public.