The Rhine Valley line would have become a lucrative access route if an eastern Alpine railway crossing had been built.

At the 2013 timetable change, the range of InterRegio and Regional services were comprehensively expanded and the lines of the St. Gallen S-Bahn were completely rearranged.

[6] The travel time of the Rheintal-Express (REX) was shortened by ten minutes to just under an hour, so that better connections could be offered in Sargans and Chur.

This required an acceleration of the Rheintal-Express, an increase in running speeds on the section to 160 km/h and the dropping of intermediate stops.

[citation needed] Three stations were closed between Buchs SG and Sargans: Räfis-Burgerau, Weite, and Trübbach.

From Bad Ragaz the trains run parallel to the A13 to Sargans station, where the line splits to Zürich and St. Gallen.

A short double track section between Trübbach and Neugrüt allows train crossings, otherwise the line to St. Margrethen is single-track.

From Buchs to Oberriet the Rhine valley line more or less follows the Werdenberger and Rheintaler canals and main road 13 as far as Altstätten.

Since then the connection between the two Altstätt stations has been provided by a short bus line operated by the Rheintalische Verkehrsbetriebe (Rhine Valley Transport Company).

The EuroCity services running from Zürich via St. Gallen to Munich are hauled to Lindau by class Re 421 locomotives registered in Germany and Austria.

DB Cargo operates its freight trains on the Kornwestheim–Rorschach–Wolfurt route with its own Swiss-made TRAXX (class 185) locomotives.

This saves a total of 40 minutes running time between Zürich and Vienna, due, among other things, to having faster turnarounds in Buchs.

Between Sargans and Rorschach, line S4 St Gallen S-Bahn services operated by Südostbahn also run every hour on a circular route with stops at all stations.

Freight traffic is heavy between Sargans and Buchs, because this is the transit route to the Vorarlberg and to the rest of Austria.