In the Christmas episode, James May is reassembling his 1970s OO-gauge Hornby Flying Scotsman trainset.
Our UK friends can simply watch it on BBC iPlayer.
I actually don't know much about British model trains, so I was quite amazed at the glowing firebox feature and especially the chuffing tender. I think the chuffing sound it creates is fairly decent! I would like to have something like that in N-gauge.