You can tell from the construction of New York City's new 7 train extension that building subways is no easy task. That makes it all the more impressive that subways were up and running 100 years ago. And even more amazingly, they don't even look all that different.
The US Library of Congress explains the context of the archival footage:
The camera platform was on the front of a New York subway train following another train on the same track. Lighting is provided by a specially constructed work car on a parallel track. At the time of filming, the subway was only seven months old, having opened on October 27, 1904. The ride begins at 14th Street (Union Square) following the route of today's east side IRT, and ends at the old Grand Central Station, built by Cornelius Vanderbuilt in 1869. The Grand Central Station in use today was not completed until 1913.
Nowadays the process of capturing that footage would be a little easier, and some of the stations might even have Wi-Fi for you to upload it to the Internet yourself. We've come a long way. But people skittering across the platform like maniacs? Apparently that's never going to change. [Buzzfeed]