THE COPPER-COLORED Stadler FLIRT Traverso trainsets that provide the only year-round passenger rail service on Gotthard Pass belong to Südostbahn, better known by the initials SOB, and are part of a somewhat groundbreaking agreement between that company and SBB, the Swiss Federal Railways.
In 2017, SBB and SOB agreed to cooperative operation of two routes, the Treno Gottardo route and one between Chur, capital of the Swiss canton of Graubünden, and the national capital, Bern, via Zurich. The latter operates as the Aare Linth, named for two rivers along the route. Under the agreement, SOB provides the equipment for, operates, and markets the routes; SBB provides a flat-rate compensation. Treno Gottardo operation began in December 2020; the Aare Linth began in December 2021.
SOB had previously operated in a relatively…