The Department of Street Railways (DSR) used to dominate Detroit’s roadways. The 1940s and 1950s were a time when public transportation was real in Detroit. Just check out the guy in the picture below (circa 1955) using a light up map to find his desired streetcar. The rise of the automobile industry is be credited with destroying the streetcar rail network as it pushed the adoption of it’s motor coach buses after World War II. During the war there was a need to conserve gasoline and rubber, so rail car was the preferred public transit option. By 1956, all streetcars had been converted to Ford motor coach buses.
The M1 Light Rail is now less of “light rail”and follows the streetcar model that can best be seen in Portland and Seattle. Hopefully future developments follow the main arteries as seen in the DSR map with streetcars running along Woodward, Gratiot, Grand River, Michigan Ave., Jefferson Ave., and Fort St. The most important consideration for future streetcar rail development should be on commuter flows.
DETROITography 
Are many of the rails still on the roadways, just covered over? Could they be uncovered and used again?
Hey Rob! I saw some when they were digging up Woodward to repave and install the Q-line. They just went right over them.
Yes, I’ve seen old rails still there in odd spots–always wondering if they could be put back in service. Hope you’re doing well, Bob!