Need some help on RR crossings

[Jim Thompson <jftpegasi@e...>]

Dear Group,
Am doing a little fact checking in the final phases of a new film called 
"Streamliners" that will air on PBS this February 4th on American Experience. 
One of our clips shows a UP train going through a crossing that is marked with 
the familiar
Railroad Crossing sign with two flashing lights below. We hope to use this 
footage in a part of the film concerning the late 30s and want to make sure 
that indeed, these signs were in use during that time period. Any insight would 
be
appreciated.
Jim Thompson