Koln south terrase
In the 1970s, Koln was the pioneer in the development and purchase of the Stadtbahn-B car and set about introducing high-level platforms on its extensive tramway system with the ultimate aim of converting the network to something resembling a full metro. Tunnel building began in earnest and trams virtually disappeared from the city centre's streets, but the scale of the task was so great that it became clear that traditional tram alignments would dominate much of the network for a much longer time than expected. Several series of Stadtbahn-B cars were delivered, and the design incorporated retractable steps to allow the cars to call at street level platforms. By the late 1990s, the number of sets delivered was still insufficient to replace all of Koln's traditional 8-axle trams, with the result that high level platforms could not be installed on many routes, including all the city centre...
