Class Ae 3/5 electric loco

Switzerland is renowned for its railroads and was certainly one of the pioneers when it came to electrifying its railroad lines. Although considered ultra-modern at the time, this traction type was confined to branch lines, the Simplon Tunnel, and the Bern-Lötschberg-Simplon Railroad up until the First World War, when Switzerland suffered greatly due to the scarcity of coal since most of the “black gold” required for steam traction had to be imported from abroad. Consequently, a decision was taken in 1918 to electrify the Swiss Federal Railways (SBB) route network, because the country had abundant supplies of hydroelectric power. In 1920, at the start of the first electrification phase, the SBB commissioned the three Swiss electrical companies Brown, Boveri & Cie (BBC), Maschinenfabrik Oerlikon (MFO), and Société Anonyme des Ateliers de Sécheron (SAAS) to develop designs for general-purpose locos that could be used on flat terrain. Unlike the side-rod drive system that had been carried over from steam loco engineering and used on most electric locos at the time, BBC and SAAS opted for single-frame locos equipped with single-axle drive systems. This groundbreaking and far more efficient drive technology had been developed by the US company Westinghouse and others from 1912 onwards for use in large locomotives. In 1918, BBC had also unveiled its equally reliable Buchli drive. For its new electric locomotive design for the SBB, SAAS acquired a license from Westinghouse. The result was an extremely compact and comparatively lightweight machine that still offered the required three driving axles and an output of at least 1,775 hp, giving a top speed of 90 km/h / 56 mph. Due to the lightweight drive, only one pilot and one trailing axle were required. The SBB ultimately ordered 26 units, which it classified as the Ae 3/5. The letter “A” stands for a standard-gauge loco with a top speed in excess of 80 km/h / 50 mph, the letter “e” stands for electric drive, while the number “3” indicates three powered axles and the number “5” the total number of axles. The machines delivered up to 1926 initially failed to live up to expectations. Although very modern in principle, the drive concept was not really suitable to run on a permanent way built during the age of steam. It was prone to squealing and creaking, particularly on curves, and damage to the running gear was commonplace. When it was time to place additional orders, the SBB therefore opted for the class Ae 3/6 I loco developed by BBC and equipped with the Buchli drive, which was not only more reliable but also more powerful and faster. As work on overhauling and upgrading the route network progressed, the class Ae 3/5 locos were finally able to run to the satisfaction of railroader operators, who soon referred to the compact locos as “petite Sécherons” or “little Sécherons.” Some local patriotism may also have played a role here, as the machines were mainly used in their home region of western Switzerland. Nevertheless, the class Ae 3/5 locos remained in regular operation until the early 1980s, a remarkable achievement. The class Ae 3/5 loco, road number 10217, has been preserved as an operational loco under the care of the SBB Historic foundation and is maintained at the train depot in Olten.