I think only about 50% of the regularly scheduled trains are currently operating on the Southern line. With a long weekend and the Asean Summit in Hua Hin expect delays. Also, trains on the Northern line are often impacted by flooding at this time of year.

The crash near Hua Hin on 5 October was horrible. Given the wreckage I'm even amazed they've got the mess cleared and the tracks repaired.