In 1879, after dynamos had become known, the firm of Siemens exhibited at the Berlin Exhibition a road about one-third of a mile in length, over which an electric locomotive hauled three small cars at a speed of about eight miles an hour. This was just before Edison had developed the efficient commercial dynamo with low-resistance armature and high-resistance field, which made it possible to generate and use electric power cheaply. Thus we see that Edison was not the first to form the broad idea of a electric railway, but his dynamo and systems of distribution and regulation of current first made the idea commercially practicable. When Edison made his trip to Wyoming with the astronomers in 1878 he noticed that the farmers had to make long hauls of their grain to the railroads or markets. He then conceived the idea of building light electric railways to perform this service. As we have already noted, he started on his electric-light experiments, including the dynamo, when he returned from the West. He had not forgotten his scheme for an electric railway, however, for, early in 1880, after the tremendous rush on the invention of the incandescent lamp had begun to subside, he commenced the construction of a stretch of track at Menlo Park, and at the same time began to build an electric locomotive to operate over it. The locomotive was an ordinary flat dump-car on a four-wheeled iron truck. Upon this was mounted one of his dynamos, used as a motor. It had a capacity of about twelve horse-power. Electric current was generated by two dynamos in the machine-shop, and carried to the rails by underground conductors. The track was about a third of a mile in length, the rails being of light weight and spiked to ties laid on the ground. In this short line there were some steep grades and short curves. The locomotive pulled three cars; one a flat freight-car; one an open awning-car, and one box-car, facetiously called the "Pullman," with which Edison illustrated a system of electromagnetic braking. [Illustration: THE EDISON ELECTRIC RAILWAY AT MENLO PARK--1880] On May 13, 1880, this road went into operation. All the laboratory "boys" made holiday and scrambled aboard for a trip. Things went well for a while, but presently a weakness developed and it became necessary to return the locomotive to the shop to make changes in the mechanism. And so it was for a short time afterward. Imperfections of one kind and another were disclosed as the road was operated, but Edison was equal to the occasion and overcame them, one by one. Before long he had his locomotive running regularly, hauling the three cars with freight and passengers back and forth over the full length of the track. Incidentally, the writer remembers enjoying a ride over the road one summer afternoon.