By the way:
http://articles.chicagotribune.com/2013-12-15/news/ct-streetcars-per-flashback-1215-20131215_1_streetcar-trolley-chicagoansBy the mid-1930s, 3,742 streetcars were running on tracks laid along 529
miles of streets in a grid that provided Chicagoans a streetcar stop within
a few blocks of where they lived, worked or shopped.
529 stat. mi. = 851 km
http://www.streetcar.org/streetcars/1058-1058-chicago-il/Chicago had the largest PCC fleet ever purchased new by one city–683 cars.
Chicago’s first PCCs hit the streets in November 1936. At 50′ 5″ they were
the longest single-end PCCs ever built, and boasted three sets of doors to
swallow crowds quickly. Each PCC carried two crew members. Passengers
boarded through three pairs of double doors at the rear of the car, paid
their fare, and moved forward, exiting through doors either at the center or
front of the car. The design worked well and Chicago stuck to it, though no
other city followed suit.
Und auch das gabs damals schon: