Daniel,
Fantastic Conversions. I especially love the Train Master, it looks beautiful!
Also, a possible idea for your Ork train (I assume you are a fan of Warhammer). What if you made a boxcar with a little sound system that played Ork-ie quotes? The top three that come to mind:
'Waaaaggghhhh" "Red makes da train go faster" "Orkz iz da best"
Your modeling skills are outstanding!
Bryce