For some reason his foamer fantasy is telling him that there are more people who need to travel directly between Broadway Junction to the Upper West Side/West Midtown than people who want to use it for its normal route. Basically it will have the same affect as a train traveling from 168th Street down to West 4th Street, and then running express and making no stops until Broadway Junction, where it will terminate.
At least he isn't closing down the transit museum and angering hundreds of people just to use it as a terminal, or sending the or to Coney Island. And hey, he's completely screwing over trains riders also for no reason whatsoever even though that line is completely unaffected, but he's sending it down to Broad Street instead of 168th Street where it would serve no purpose!