Today's MTA subway system is a single entity, but until 1940, the system was composed of three competing organizations. Unification brought together routes maintained by the privately-owned Interborough Rapid Transit Company and Brooklyn-Manhattan Transit Corporation, and the city-owned Independent Subway System.
Take a crash course on these and other subway fundamentals through the New York Transit Museum, as you tour portions of each of the original system with historian Andrew Sparberg.
