I found this vintage General Motors transit bus photograph at my Link Page Northern California Bus Fans, which is located to the right of your computer screen at www.norcalbusfans.com
The cities of Chicago Illinois and Philadelphia Pennsylvania shared many similarities when it came to transit bus color schemes, and still do today.
Seen here is a 1960's era General Motors 40 foot TDH "New Look" fishbowl windshield bus from the former Philadelphia Transit Company.
The Chicago Transit Authority shared the same model and color scheme on the GM new look buses during the 1960's. Except for the PTC markings, one could mistake this for a CTA bus.
A very tasteful transit company color scheme that I had grown up with here in the windy city