The scenes shot at Marylebone station showing firstly the soldiers departing to fight in France and secondly the wounded soldiers returning from France, were one of the most expensive outside broadcasts for a drama series at the time. They were filmed on a Sunday when fewest British Rail trains used the station. Filming had to stop every hour to accommodate the hourly British Rail train from Princes Risborough; the hourly service from Aylesbury did not run on a Sunday at the time. Judiciously-placed artificial smoke was used to conceal any modern features of the station which could not be covered by the art department. Many extras were used, firstly for the departure to France when they were dressed in immaculate uniforms and filmed on one side of the train. Then for the scenes of soldiers returning from the front some months later, the same extras were made up with horrific war wounds and dressed in tattered, filthy, blood-stained uniforms. The other side of the train, suitably "distressed" by the art department and shown arriving at a different platform, was used for these scenes.