Now here is an undertaking--the harnessing of the mountain streams of Montana and Idaho and Washington toward the pulling of the freight and the passenger traffic of the newest and best constructed of our transcontinentals for half their run. Translated into the comfort of the passenger, it means that for a long night and two days that are all too short, the trail of the Olympian is dustless, smokeless, odorless; it means that the abrupt stops and jerking starts of even the best of passenger engineers are entirely eliminated. The electric locomotive starts and stops imperceptibly. It is one of the very strongest points in its favor. And when you come to freight traffic--the earning backbone of the greater part of our railroad mileage in the United States--the operating advantages of the electric locomotive over its older brother of the steam persuasion are but multiplied. The electric locomotives of the Milwaukee, being the newest and the largest yet constructed, have missed none of these advantages. As the greatest of all these, take the single tremendous question of regenerative braking. Up to this time no one has ever thought of transforming the gravity pull of a heavy train going downgrade into motive energy for another train coming uphill. Talk about visions! How is this for one? Yet this is the very thing that the Milwaukee is doing today--upon each of its heavily laden trains as they cross and recross the backbone of the continent. Its great new locomotives take all the power they need for the steady pull as they climb the long hills; but when they descend those selfsame hills they return the greater part of that power--sixty-eight per cent, if you insist upon the exact figure. Perhaps you drive an automobile. If so you probably have learned to come down the steeper hills by use of compression--by a reversal of the energies of your motor, until it is actually working against the compelling force of gravity. Your brakes are held only for emergency. That is the only part which the brakes on a Milwaukee electric train play today. The electric locomotive in a large sense is its own brake. In other words, a turn of the engineer's hand transforms its great motors into dynamos; gravity pulls the trains and forces the dynamos to turn--back goes the sixty-eight per cent of current into the copper trolley-wire overhead; over on the other side of the mountain somewhere a train ascending toward the summit feels instantly the influx of new energy and quickens its speed.