This is the length of the Martigny-Chamonix route, comprising 18 kilometres on Swiss territory and 20 kilometres on French territory.
The journey time between Martigny and Chamonix is 90 minutes. It takes another 45 minutes to reach St-Gervais, which is the terminus of the Mont-Blanc Express. In 1908, it took 3.5 hours to reach Chamonix from Martigny.
The track gauge is 1 metre, it is a metre gauge railway (7% adhesion ramp) and rack and pinion (Strub system, 2.5 km between Vernayaz and Salvan, 20% ramp), direct current line at 850V
The Martigny-Châtelard line was built in only 4 years (1902-1906) and inaugurated on 18 August 1906, it includes 6 bridges, 5 viaducts, 12 tunnels, 16 galleries. On the French side, the line was opened in 1901 from St-Gervais to Chamonix, in 1906 from Chamonix to Argentière and in 1908 from Argentière to Châtelard-Frontière. It comprises 9 tunnels.