The first line was the Jaffa–Jerusalem railway, followed by the Jezreel Valley railway, which formed part of the greater Hejaz railway. World War I brought the creation of multiple new lines out of military needs: Portions of what is now the Coastal railway were built simultaneously by the Turkish and British and later merged during the British Mandate. Southern lines were also built by the warring states—from the north by the Ottomans, and from Rafah in the west by the British. Beginning in the mid-1960s, railway development stagnated, and a number of lines (notably, the Jezreel Valley railway and most of the Eastern railway) were abandoned altogether. Development restarted in the 1990s, the opening of Tel Aviv's Ayalon railway in 1993 signaling a new era of rail development. Lines under construction in the 2000s include the high-speed railway to Jerusalem, an extension of the coastal railway directly from Tel Aviv to Ashdod through the northern Shephelah, and a line from Ashkelon to Beersheba via Sderot, Netivot and Ofakim, as well as a complete reconstruction of the line from Lod to Beersheba. These and other extensive infrastructure improvements led to a 20-fold increase in the number of passengers served by Israel Railways between 1990 and 2015. After numerous delays due to the complexity of the project, a new line between Tel Aviv and Jerusalem opened in 2019. This line is the first electrified railway ever built in the country. Israel Railways has ordered Bombardier Traxx electric locomotives for use on this line and for other lines to be converted to electric operation. All existing and future electrified mainline railways in Israel use 25 kV 50 Hz overhead electrification. Light rail/subway The 13-kilometre-long Jerusalem Light Rail system began operation in August 2011 and is being extended. The construction of the Tel Aviv Light Rail and the Tel Aviv Metro, serving Tel Aviv and surrounding cities, in underway and the first line, the Red Line, is set to open in 2023. A significant portion of it will be underground. Haifa's Carmelit, an underground funicular railway, is currently the only subway line in Israel. It is listed in Guinness World Records as the shortest subway system in the world, being the second smallest track network (after the Tünel in Istanbul,) but being the smallest "system" by virtue of being the only urban rail network in the city. The Haifa–Nazareth railway, a planned light rail