Rule #1 in TV, never invent when you can copy.
Train 48 is, as I understand it, a direct licensed copy of a program from Australia (the one with the kangaroos) if you read the credits I believe they credit the original show.
It's an interesting idea, take a bunch of improv comics, create a persona for each one, write a broad plot outline and let the actors loose to improvise. Does it actually work? well of course not, but it is an interesting idea.