Here's a video from 1905 of a NYC subway car going from 14th Street to 42nd Street. It's funny to see all the men in suits and hats running for the train...it takes some of the formality out what seems from photographs to be a more dignified time. Also, anyone know what line/train this is?
Update: The inbox consensus seems clustered around the opinion that this train is running on the contemporary 4/5/6 line. Here's a 1904 map which shows the then-IRT line in question (in red). At 42nd St, the line runs crosstown to Times Square and then up the 1/2/3. (thx jason et al.)