of the Air Line started, electric railroading alreay had made huge progresses since 1893. In 1903, railcars from Siemens & Halske and AEG ran at above 200 km h on the military experimental Marienfeld–Zossen outside Berlin (see Land speed record for rail vehicles). However, the physical laws which made rising infrastructure requirements and costs with rising speeds, were well-known by the railway and interurban companies. Therefore, European high-speed electrical railway projects