All aboard the crazy train! Fresh off his Oscars hosting gig, Neil Patrick Harris joined forces with Funny or Die for a video about being #ThomasObsessed — Thomas being "the Tank Engine" from Wilbert Awdry's Railway Series books and TV spin-off.

In the clip, created in honor of Thomas the Tank Engine's 70th anniversary, Harris stops by a Fan Day Celebration to chat with some fellow (but much younger) "Tankies." It quickly becomes clear, however, that the 41-year-old How I Met Your Mother star's fandom has gone a little off the rails.

Case in point? After one of the kids in the group declares that Thomas is "the fastest," Harris (who has 4-year-old twins with husband David Burtka) very sternly corrects him.

"Hold on, hold on. Thomas is very fast, but not the fastest," he says. "Thomas is an E2 class tank engine, which was made for short-haul freight journeys and shunting. So fast, yes. Fastest? Eh, not quite."

When the kid continues to insist that he's "the fastest," the actor grows impatient. "I don't want to argue with you, but I'm the oldest Tankie here, so I know a lot more than you do," he scoffs.

His anger over their lack of tank engine knowledge (Thomas is cerulean, thank you very much) escalates to the point of actual steam coming out of his ears. "You are not Tankies! If anything, you're a bunch of troublesome trucks," he fumes, tearing down the celebratory sign behind him. "It's a slap in the face to Thomas!"

Watch the funny video above!