Originally I thought this picture featured an early Griffith Observatory in the background, but I think after closer inspection that it is not Griffith Observatory. It is possible it is the Brackett Observatory in Pomona, CA, which was part of the Pomona College campus. Built in 1908, it was named after Frank P Brackett, one of the original staff members at Pomona College when it was founded in 1888. He taught at the school from 1888 to 1934, an impressive 46 years of teaching!
I believe the photos below are from the same day trip as the person featured is wearing the same clothing. I have no idea where this railway track may have been. There was a railroad ‘boom to bust’ in the Claremont & Pomona areas prior to the college being built in the 1880s, but this looks more like a street car.
Frank Parkhurst Brackett entry in the Publication of the Astronomical Society of the Pacific