Several incidents have coloured the history of the line. On 1 August 1904 the passenger building of Bellegarde station went up in flames, to be rebuilt in 1913. 1922 saw the two biggest incidents on the line, a landslide and a tunnel accident. On 11 April, a huge landslide near Neyrolles station completely cut the line. On June 3 a new alignment was opened. The most difficult operational feature of the line was its longest tunnel, the Mornay tunnel. Over 1300m of the tunnel is at 2.4% gradient; running towards Bellegarde, steam locomotives had to operate at full power, filling the tunnel with smoke. The natural ventilation was poor. In May 1922, 7 members of a train crew were asphyxiated and died. Subsequently, a special ventilation plant was opened in 1924, one of only two of it kind in France. It blew air into the tunnel when trains were passing through in the Bourg to Cluse direction.