\r\n\u00dcstra placed an initial \u20ac126m order in 2011 for 50 of the high-floor bi-directional vehicles with two options for a total of 96 additional units. The first option for 50 vehicles was exercised in November 2013, followed by the second option for 46 vehicles in June 2017.\r\nThe first TW 3000s entered service in March 2014 and \u00dcstra has so far received 72 of the 25.2m-long 600V dc LRVs, with the vehicles in service on lines 3, 4 and 7. \u00dcstra says the trams will soon be introduced on lines 4 and 5, while Line 8 will be ready for TW 3000 operation next year.\r\nThe TW 3000 fleet will reach 110 vehicles by the end of this year and 146 by the end of 2019.\r\nLower Saxony Transport Authority (LNVG) has agreed to cover 50% of the cost of the latest order, leaving \u00dcstra to provide just \u20ac462,000 from its own resources.\r\nIn the longer-term, the TW 3000s will replace \u00dcstra\u2019s remaining Duewag TW 6000 trams, 25 of which are due to be withdrawn this year. However, the rate of TW 6000 withdrawals will depend on ridership growth. \u00dcstra\u2019s previous calculations for fleet demand assumed average passenger growth of 1% per year, but ridership increased by 3.9% in 2015 and 3.8% in 2016.