Car Stop Signs

[Kenneth and Tracie Josephson]

Here is a Pittsburgh Railways car stop sign on eBay:

http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=264334429

The person selling it was told (third hand information) that this
particular sign originated in San Francisco and was removed during the
1950's.

Since Pittsburgh Railways had corporate ties to the Market Street
Railway, is it possible that both systems used these signs at one time? 

I don't ever recall seeing a picture of these signs anywhere else but
Pittsburgh. Check it out! Ken J.