Chicago rapid transit Ravenswood train at Belmont stop, 1931
On March 7, 1931, a train (4000-series cars) to downtown and back to Ravenswood, via express, stops at Belmont while a train of wooden 'L' cars, possibly to Howard, leaves the station heading north following a recent snow.
This photo was taken 12 years before the State Street Subway would open in 1943, so all trains would continue downtown via elevated, the same way Brown and Purple Line trains do today--express trains would make fewer stops than local trains did, as local trains would stop every station.
At Chicago, the four-track line went down to two tracks and both local and express trains would then need to share a single track in each direction the rest of the way into the Loop.
Note: Chicago Elevated Transit = 'L' New York Elevated Transit = 'EL'