The incident occurred at around 10.45am at the St. Margrethen station while the Briton was being escorted by two conductors from a train travelling to Munich from Zurich, cantonal police said.
On the station platform, the man struck one of the conductors, a 58-year-old man, with his skateboard, knocking out several teeth, police said.
He then fled from the scene.
Police arrested him shortly afterward.
The injured train conductor was taken to hospital for treatment.
The British man remains in detention while police undertake an investigation to clarify the exact circumstances of the case.