Work to reconnect two parts of a railway line which was divided into two over three decades ago is set to begin.
A new bridge, in Loughborough, is the first stage to rejoin the 18-mile (29km) railway, described by GCR as the "UK's only main line heritage railway".
The £8m project is due to be completed by 2019.
One section of the railway runs from Leicester to Loughborough - the GCR - and the other from Ruddington, in Nottinghamshire, to North-West Leicestershire - the GCRN.
Separating the two railways is the gap where tracks, embankments and bridges were removed in the early 1980's.
History of the line
- Opened in 1899 - linking Manchester, Sheffield, Nottingham, Leicester, Rugby to London.
- Closed in 1966, but a section from Leicester to Loughborough was saved by a group of enthusiasts.
- In 1976, Great Central Railway PLC was formed, which runs trains from this section of the track.
- In 1989, Great Central Railway Nottingham took over the former MOD site at Ruddington - the last MOD train ran out of there in 1983.
- Services are pulled by steam or diesel locomotives aiming to recreate the experience of train travel from the 19 Century.
- It's the only place in the world where full size steam engines can be seen passing each other.
- Around 130,000 people visit the railway each year. Source: GCR and GCRN
The new 30m bridge will carry a single track of the heritage railway over the main line between Derby and London St Pancras.
Bill Ford, of GCR, said the start of the project was "a very exciting moment".
"We have cherished this vision for decades, so to finally make a start on the ground is very important for us," he said.
Nicky Morgan, MP for Loughborough, will perform a traditional Victorian style "turf cutting" ceremony to mark the start of the work.
Paul Kirkman, of the National Railway Museum, said: "Leicester had one of the world's earliest railways and was also a hub of the Midland line.
"This joining of the line seems another positive step towards making the area and region rich in railway heritage, and inspiring a new generation to get involved in our nation's railway story."