Chicago's Surface Lines by Alan R. Lind provides a technical and detailed look at the city's streetcars. Most of the Chicago El dates back nearly a century, but pre-1950 or so, streetcars did the bulk of our transit work. The book has photos of every single streetcar design ever used in the city and through these photos, offers a fascinating glimpse at the way many of the routes, both the physical routes and the sites that populate them, have evolved over the last century, providing a history that goes much deeper than the design of the cars alone. Who knew that bland condo or mini-mall on the corner used to be something interesting? Many current CTA bus routes owe their numbers and basic routes to the streetcar lines that preceded them, which in some cases date back to the turn of the 20th century. Chicago had the classic red trolley car, but also later designs popularly known as The Blue Goose and The Green Hornet.