Oh yes, DS is typically car/digger/train mad. I remember going for one of his developmental check ups (2 years?) and the tick list was "knows fifty words" - I started counting & got to over fifty just on vehicles. Was very pleased with myself until I realised that was about all the words he knew!
Car journeys are now spent correcting me..."No, mummy, that's a grab-lorry / flat-bed truck etc etc"
And don't get me started on Thomas trains...he goes through the website which lists all of them and I have to read out their profiles. Anyone know who No 8 is by the way? It's bugging him that I don't know...