The first section of the line, between Sondrio and Colico, was opened in 1885.

It was completed in 1892–1894 with the section from Colico to Lecco, where it was connected with the rest of the Italian network.

[2] It is single track other than at main stations which have passing loops.

The section from Tirano to Sondrio had a different origin, being opened in 1902 as a private railway by the Società Anonima per le Ferrovie dell'Alta Valtellina (FAV).

Media related to Tirano–Lecco railway at Wikimedia Commons