Roy hears about the golden age of steam with Shaun Sewell.
Cardiff astrophysicist Prof Chandra Wickramasinghe discusses the latest images of Pluto.
Music and chat with Roy and guests, plus Choir of the Week All That Malarky.
Roy hears from Professor Iestyn Jones about his career change from actor to archaeologist.
Roy looks ahead to the Welsh Proms with conductor Owain Arwel Hughes.