On the line running down Georgia Avenue from Silver Spring to 7th Street N.W. in D.C. the change over took place just north of Florida Avenue near the front of Griffith Stadium. They would lower the pole and a worker standing in a pit between the rails would hook up the foot, which ran in the center groove.

I wonder how it is possible to get such huge format pictures (and so sharp) from what is called a "Medium-format safety negative"? Or is such a negative not so medium at all?

[It's 3 by 4 inches. - Dave]

Exactly. In the city, the DC streetcars got their juice through a "foot" that ran in that groove. When they moved into more suburban areas they'd put the pole up and get power from the overhead wires.

This was done to remove the overhead wires from busy streets where they were often in the way or subject to being hit by trucks, ladders etc. Not to mention the overhead wires were ugly.

These streetcars are PCC cars, probably built right around the time of WWII. A very modern design with rubber-centered wheels and a steel frame for smooth running. After the DC streetcar system closed in the 1960s, most of these cars were sold to operators in Europe, where I think some still are running. I think this same basic design was built in the Soviet Bloc into the 1980s.

It took me a while to figure out what was bothering me about this photo. The three trolleys all have their poles down so they aren't drawing power from overhead. Then I noticed the tracks that they're running on. There appears to be a third rail or perhaps a groove set below the pavement surface where presumably they draw power. The fact that the cars still retain their poles would seem to indicate that there were areas or routes where this arrangement was not the norm. I'm no expert but this sort of arrangement seems quite unusual to me.