It's the first regular train service to link Wareham with Swanage, in Dorset, in 45 years.
Civic dignitaries joined rail enthusiasts today for the launch of the new service which marks the the culmination of years of campaigning and hard work.
Much of the branch line was torn up after British Rail closed the route in 1972 but it has gradually been rebuilt and improved and now represents an amazing dream come true.
As Richard Slee reports.
Richard spoke to Peter Sills, Colin Stone and Peter Frost, all railway volunteers. He also spoke to Director of Project Wareham Mark Woolley.