Hi Mick,
Werdenberg is so small i belive you can't find it on a timetable, there is no station as well as a bus stop. It is between the towns "Buchs" and "Grabs" you will find it on the map close to the border to Liechtenstein in the far east of Switzerland. It is called the smallest city of Switzerland the reason for this is some centurys back it was an important marketplace and it received the right to be a city.
Kind regards Hans