Around 145,000 people used Viennas 24-hour underground service on New Years Eve, it has been announced.Public transport agency Wiener Linien said today (Tues) the 145,000 registered passengers made last Fridays New Years Eve the busiest night since it started offering U-Bahn operations throughout the night on weekends and before national holidays.Around 750,000 celebrated New Years Eve in the Austrian capital. Wiener Linien offered a 24-hour underground service on that day of the year as an exception before.Wiener Linien also announced the average number of passengers of the 24-hour service were 45,000 people. The company claimed there has been no significant increase of violent incidences in trains and on platforms in the first four months of the around the clock weekend U-Bahn operation.The nonstop operation on weekends is costing an overall 10.7 million Euros a year as Wiener Linien decided to continue offering a reduced “Nightline” bus service as well. Vienna taxi association chiefs expressed fears the increased service will lead to a decline in customer figures for their branch.Viennas U-Bahn service is 75 kilometres long and features five lines. The lines do not have specific names. They merely have a number and the prefix “U” (for U-Bahn). Additionally, each line can be identified by a colour. There are currently five lines, U1, U2, U3, U4 and U6. There have been numerous projects for a line U5, with a variety of suggested routes, but all these projects have been shelved, and it is unlikely to be built in the near future.Public transport had a share of 35 per cent of overall traffic in the city in 2009, up by six per cent in 1993.The ruling Viennese Social Democrats (SPÖ) decided to introduce the 24-hour underground service after 54 per cent of Vienna residents spoke out in favour of such a reform of schedules in a referendum last February.