
Built at the beginning of the 20th century, the Train Jaune railway line was
intended to connect the high Catalan plateaux with the rest of the "département".
Work first started in 1903 and by 1910 progressed as far as linking Villefranche
to Mont Louis.
The
line was only finally completed in 1927, by reaching Latour de Carol, and it
still follows its original route in a very uneven environment.

Thus, building this line has required the construction of the 650 civil engineering
works, including 19 tunnels and two remarkable bridges: the Séjourné
Viaduct and the Gisclard Suspension Bridge, to enable the Train Jaune to overcome
the contours of the scenery.