I was unaware that Thomas Edison had built an electric railroad at his Menlo Park, NJ, research lab in 1880. Growing out of his work on electric motors, it ran for 90 rods and presumably contributed to the developments which would make electric traction a competitive technology. This short 1909 article from POPULAR ELECTRICITY, though aimed at children, provides the basic information. I've enlarged the picture of the locomotive itself, so that you can better see its odd configuration. It's interesting to consider that in 1909, the subject of the article was not even thirty years in the past; it's as if we were considering a technology from 1984 as ancient history.
As always, click an image to see a bigger version.