Actually I thought he was going to be immediately hit by a train as soon as he said "I love trains". Though of course he should have said "I like trains" to be a proper asdf movie reference.
If I might make a suggestion, you might consider taking on Bananas in Pyjamas in a similar parody. In college, a friend of mine had a hilarious skit where he impersonated the voices and act out them doing all sorts of horrible sexual acts in an orgy or something. Damn but I wish I remember much of his routine but it has been so long so I don't remember the details, I just remember that it was very funny and that his accent was bang on.
Very creepy. Which of course is what you were going for, so nice job there. The only thing that gave me pause was why would the doctor even admit this was possible. I was kind of expecting her to be like "obviously I can't do that, that's impossible, if I could do something that amazing I could just save his life as he is". It seems to me that a better explanation for his origin would be an ill-conceived birthday present or something. That he'd just wake up as a train, not after having been hit by a train, and the boss would be like "happy birthday!" But of course there's no good logical way to explain something that at the end of the day is really very weird.