I found this photograph at my Link page Northern California Bus Fans, which is located to the right of your computer screen at www.norcalbusfans.com (A really cool site!)
I was born in Chicago Illinois during the year of 1962, and some of my earliest memories from my childhood, were riding and observing several of the first generation Chicago Transit Authority buses that were still in daily service during the 1960's and early 1970's era.
The Chicago Transit Authority began operations in the year of 1947, upon the acquisition of the Chicago Surface Lines Company (Streetcars and some buses.), and the Chicago Rapid Transit Company (Elevated and subway rapid transit trains.) During the year of 1952, the CTA would also acquire local transit bus operator Chicago Motor Coach Company, and quickly phase out the remaining electric streetcar system in Chicago for good by 1958, converting to 100 percent motor bus operation on Chicago city streets.
I fondly remember riding several of the early CTA buses during the 1960's, like the unique propane gas powered transit buses from the Twin Coach Company, and the successor company Flxible Twin Coach Company built from 1953 to 1959.
These buses had quiet running engines, but had idled rough and suffered from sluggish acceleration. Mechanical problems and age found these buses retired from daily transit operations by 1973.
I could still remember those high mounted windows, which required this young lad to either kneel on the seat, or sit on my Mother's lap just to look out the windows on any given trip.
I miss these buses today.