I think autists take an interest in public transportation because it's a complicated yet understandable system, especially trains. Short but wide history, interesting mechanics, complex schedules, and they GOTTA GO FAST. The whole system has many assets to dissect, analyze and understand, yet none of them are abstract - it's all basically numbers.
I can definitely see why people that have a hard time understanding and exploring abstract, emotional and social themes but have a need to fixate on details and mechanisms (that are intricate enough, like trains, but not as complex as, say, medical science) might be interested in that.
Chris on the other hand, well...
For starters, I simply think he is too stupid to understand something as complex as the ins and outs of public transportation. Secondly, Chris needs flashiness, and trains and buses are a bit too dull for that.
And most importantly, I think, Chris' head is already way too "full" to care about any other subject other than the detail-full lore of the fiction he is into. He has to memorize and understand all the story and lore of all those stupid kids' shows, movies and video games he loves so much, not to mention fucking CWCville and its' characters, which at this point probably has more characters and events than the Iliad and the Odyssey combined.