SBB RABe 503 xxxMoerschwil Moerschwil

As EC197 Zurich HB (17:33) - Munich Hbf (21:04), this connection is one of the few services in double traction with RABe503 "Astoro" and without a stop at St. Margrethen border station. The train crosses the 568 metre long Galgentobel viaduct. This replaced the single-track line in the Steinach Valley along a creeping slope, which led to service interruptions on several occasions. This unstable area was spanned by an emergency bridge, which was built in the summer of 1975. The final solution to this problem was the realisation of a double-track viaduct made of prestressed concrete with ten pillars, which bypassed the entire unstable slope area as a route variant. The Galgentobel Viaduct was opened on 4 April 1982 after a load test. This was carried out with twelve Ae 6/6 locomotives coupled together, which corresponded to a mass of 1,440 tonnes over 220.8 metres (i.e. around 6.5 t/m). The bridge deflected by 15 millimetres, which corresponded to the calculated values.

The second track was not laid initially. The double track was extended in the same year 1982 from the newly created Engwil service station (after the bridgehead on the St.Gallen side) to Mörschwil. It was not until 1994 that the remaining section between Mörschwil and the Horchental service station was upgraded to double track.