They have 2+2 reversible seats.

These were the trains I rode the most often, when I was commuting from Newcastle three or four days a week to teach at the Central Coast, and when I had to go to Sin City. Indeed, this was the last type of train I rode in Australia, since there was trackwork the day I flew out and it was a bus from Sydney Central Station to the airport.

I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.