People tend to check in during these times:
The 42nd Street Shuttle is a New York City Subway shuttle train service that operates in Manhattan. It is sometimes referred to as the Grand Central / Times Square Shuttle. It runs at all times except late nights, connecting Times Square to Grand Central under 42nd Street.
Start to run like its going to leave, and watch the whole crowd start running ;)
During rush hour the shuttles come fast - make sure you check the digital signage to see which track the next train will be on.
take this to get from time square to grand central and vice versa!