The name is an abbreviation of the English/German project title "Computer Integrated Railroading - Erhöhung der Leistungsfähigkeit im Kernnetz der Eisenbahn" (Computer Integrated Railroading - Increase Capacity in the Core Railway Network). Being an extension of LZB it is also called LZB-CIR-ELKE further abbreviated into LZB-CE. CIR-ELKE includes the following improvements:  The original LZB system was designed for permitted speeds up to and gradients up to 1.25%. The Cologne–Frankfurt high-speed rail line was designed for operation and has 4% gradients; thus, it needed a new version of LZB, and CIR ELKE-II was developed for this line. CIR ELKE-II has the following features:  The LZB system has been quite safe and reliable; so much so that there have been no collisions on LZB equipped lines because of the failure of the LZB system. However, there have been some malfunctions that could have potentially resulted in accidents. They are:   The following lines of Deutsche Bahn are equipped with LZB, allowing for speeds in excess of 160 km/h (providing the general suitability of the track):   Note: "italics" indicate the physical location of an LZB control center. The West railway (Vienna–Salzburg) is equipped with LZB in three sections:    In addition to mainline railways, versions of the LZB system are also used in suburban (S-Bahn) railways and subways. Tunnels in the Düsseldorf and Duisburg Stadtbahn (light rail) systems, and some tunnels of the Essen Stadtbahn around the Mülheim an der Ruhr area are equipped with LZB. With the exception of line 6, the entire Vienna U-Bahn is equipped with LZB since it was first built and includes the capability of automatic driving with the operator monitoring the train. The Munich U-Bahn was built with LZB control. During regular daytime operations the trains are automatically driven with the operator simply starting the train. Stationary signals remain dark during that time. In the evenings from 9:00 p.m. until end of service and on Sundays the operators drive the trains manually according to the stationary signals in order to remain in practice.