In 1899, Siemens & Halske and its competitor AEG were each awarded an order to equip a high-speed railcar. The first test series began in October 1903. On a 23-kilometer stretch of test track between Berlin-Marienfelde and Zossen, speeds of more than 200 kilometers per hour were reached for the first time in the history of rail travel. The railcar’s single-phase alternating-current system was a milestone in the design of high-performance traction motors.
“A railway without steam or horses” – The future belongs to the electric locomotive
At the end of 1866, Werner von Siemens discovered the dynamoelectric principle, and just a few years later, this insight served as the foundation for developing a new drive technology for transporting people and freight: the electric motor.
In 1879, Siemens & Halske unveiled the world’s first electric locomotive at the Berlin Trade Fair. In 1881, the world’s first electric tramway went into operation in Groß-Lichterfelde, while the first electric subway on the European continent made its debut in Budapest in 1896.
The electric locomotives quickly superseded the steam-driven “iron horses” that had previously been considered a symbol of technological progress. The “railway without steam or horses” was unheard of and revolutionized rail travel in Europe. Horse-drawn streetcar carriages were equipped with electric motors, and electric locomotives were increasingly used in mining and industry as well.
However, the voltage of the overhead contact line for the direct-current system that was commonly used at the time was too low for long-distance travel – which required standard-gauge railways for passenger and freight transport. The direct-current system’s maximum voltage of 600 volts was not sufficient to transmit the power needed to drive fast, heavy trains across long distances.
Alternating current instead of direct current – “More, faster, further”
As early as the 1890s, the engineers at Siemens & Halske – above all, Walter Reichel, who developed a special bow collector – looked to the alternating current system to increase the speed and transport capacity of electric railways. The use of single- and multi-phase alternating current made it possible to select a relatively high voltage for the contact line. Transformers in the locomotive then converted the voltage to the level required for the traction motors. Railcars with high-voltage three-phase alternating current were tested on the premises of the Charlottenburg plant and at the company’s test track in Groß-Lichterfelde.
In 1899, these tests gave rise to the establishment of the Research Association for High-Speed Electric Railways (Studiengesellschaft für elektrische Schnellbahnen, or StES), whose members included Siemens & Halske and its competitor AEG as well as several German banks and mechanical engineering companies. To test the operation of fast electric railways, the association commissioned each of the competing electrical engineering companies to equip a high-speed railcar.
Both vehicles were ready for operation in the fall of 1901. The high-speed railcar from Siemens & Halske looked like a conventional high-speed carriage and was aerodynamically shaped in the front. Nearly 24 meters long, it weighed 89 tons and had wooden seats for 48 persons in the passenger compartment between the two driver’s cabs. The carriage rested on two three-axle bogies, for each of which power was supplied via three bow connectors.
Test runs at world-record speed – The Zossen high-speed railcar reaches 210 km/h
The first test runs were conducted on a section of track on the Royal Military Railway that was specially equipped with a three-phase overhead line. In early October 1903, on the 23-kilometer stretch of test track between Berlin-Marienfelde and Zossen, speeds of more than 200 kilometers per hour were reached for the first time in the history of rail travel. This was not only a world record but also impressively demonstrated that high-voltage alternating current was suitable for the high speeds that were envisioned for long-distance travel.
Nevertheless, because the alternating-current technology was not yet mature, the successfully tested rail electrification system did not go into real-life operation. There were two major arguments against using the system in everyday rail operation: multiple poles were required to support the overhead lines, leading to complications at the track switches and intersections, and the ability to regulate the rotational speed of the electric motors was limited.
The single-phase alternating current system prevails – Real-life operation can begin
As a result, the single-phase alternating-current system gained acceptance. In 1912, a cross-border agreement was reached, establishing a 15-kilovolt, 16.7-hertz rail electrification system that is still used in Central Europe today. A single-pole overhead line supplied power for the system. The use of single-phase alternating current made it possible to transform the voltage for the low-loss control of rotational speed, while the low frequency allowed for the construction of powerful traction engines early on – thus enabling the entire system to be flexibly adapted to the relevant route requirements.