Some titles available in Google Books; there's certain to be more.
Electric Railway Journal. v.33, 1906. v.42, 1913. v.45, 1915.
Street Railway Journal. v.21, 1903.
Electric Railway Service (Detroit United Lines). 1917. This last one is remarkable as an in-house PR newsletter, full of editorials railing against the Detroit Evening News, and with notably precise accounting for the delays (and causes thereof) on streetcar lines. "The Lying Evening News Still Continues to Lie" was a headline from 1914.
Print archives include the Plymouth (Michigan) Historical Museum, with a finder's aid available, and the University of Michigan Transportation History Collection.
