There are twinning certificates displayed at each railway. Volunteers from both railways arrange visits to celebrate the two lines' common interests.
Our film first visits the P'tit Train de la Haute Somme at Gala time when five locomotives were in service and Decauville No. 5 was baptised with champagne on re-entering traffic after restoration.
There was an intensive train service up the 1:30 gradient to the Plateau with freight trains as well as a passenger service.
At Leighton Buzzard there is coverage of the sand demonstration at Stonehenge Works re-enacting the reason the railway was built.
The line is filmed from end to end and special events include Santa Trains and the Indian Day Gala. Eight locomotives are seen in action.