That rail on 105th Ave. was SP and left the main line at Stonehurst. It served the Chevy plant at 73rd Ave. and also Fisher Body at Dutton. To reach Bancroft from 105th, it used a right of way between those points.

At some point the connection to SP was severed (and the grade crossing of the WP). Track connected to WP instead.

I don't know when the last use of the line was.

As for Dutton and Bancroft (in San Leandro) that was the terminal of the SP electric Red Train (known as the 7th St. - Dutton Ave. line). The double track ended just west of Dutton and there was a crossover switch. No balloon track. The shot of the plaza (which appears to be Victoria Ct.) was a stop on the SP. Just a fancier stop, probably part of a new subdivision at the time.

Red electric trains ran all the way from Dutton to Oakland along Bancroft (sharing with freight movements between the Stonehurst Branch and 73rd Ave.) West of 73rd, the electrics ran via Bancroft and Bond (now renamed) to the flatiron building near 46th and E. 14th, then to Melrose station and onward to the Pier and later San Francisco.

Key System extended their A line from Lake Merritt out E. 14th to 46th and tied into the ex-SP to operate to Havenscourt Blvd. following SP's discontinuance of the Dutton line in 1941. Key cut back their A line to Oak St. in 1950 or 1951.