We got to Hua Hin station, and Mrs BB goes to the ticket desk, and requests 2 2nd class tickets to Prachuap. They said no 2nd, only 3rd class available. I said OK, and the deal was done. 19 Baht for me, and my wife travelled free

I went to study the departures screen, and sure enough the 11:30 train was displayed - of course, it was running the mandatory 30 minutes late, but the journey time was 1 hour less. I sent Mrs BB back to the ticket office, and told her to book us onto the correct train. She talks to the clerk, and calls me over. Its 323 Baht each. Of course, I asked why, but there was no sensible reply. I thought about it - 323 Baht equates to about £6.50 each, so I thought, don't be a cheap Charlie, just hand the money over, which I did. Any other decision would have seen us having to abort our day out.
When we boarded the train, it was comfortable, air conditioned and all inclusive food and drinks (water) were served before we passed Khao Takiap.
The trip home was the same cost etc. How do they justify such a hike in costs? The more expensive trains were fully loaded both ways, so must be very popular. My theory is that you pay for the train's entire journey, regardless of where you board and alight.
As a bye the bye, when we boarded the train home, they turfed 2 people out of our seats - one was a pregnant woman (about 8 months). I was considering giving the seat back to her, but it soon became clear that she was travelling on a freebie as a friend of the hostess. I'd paid, and she hadn't, and none of the Thais on board (many a lot fitter than me) offered to give up their seat for her. This is still playing on my conscience a little, but I wonder what the reaction would have been (especially form my wife) if I had stood up again.