A closer photo of the U. S. Electric Signal as mentioned in the previous photo. This was made in 1919 by the United States Electric Signal Co. of West Newton, Mass. The Portland, Oregon streetcar lines were the only west coast trolley lines to use this type. They use D.C. power and employ a "walking beam" style of relay. (I won't go into details!) When the red light indicates stop, a red disc also flips upright inside one of the round glass windows on the sides. Likewise for the yellow proceed indicator. We had some operating in the previous trolley museum facility (we have the original electrical schematic) but we relocated the museum in 1997 and have not re-installed them yet. Click NEXT to see the other signal (No. 1) in service.