Characteristics
The northern portal of the tunnel is located at elevation of 562 m.a.s.l., while the southern one is found at 575 m.a.s.l. The tunnel tubes are not equally long - the northbound tube is 5,821 metres (19,098 ft) long, while the southbound one is somewhat shorter, as it is 5,780 metres (18,960 ft) long. The tunnel tubes are excavated 25 metres (82 ft) m apart, and are linked by 6 vehicle passages and 14 pedestrian passages.
The tunnel comprises 7.7 metres (25 ft) wide carriageways, permitting driving speeds of up to 100 km/h. The tunnel features an autonomous drainage system channeling water accumulating during cleaning of the tunnel, as well as seeping water and liquids spilled in accidents or used for firefighting.
The tunnel was executed using New Austrian Tunnelling method, by means of drilling and explosive blasting. Numerous caves, caverns and other speleological structures were found during the construction, but all of those were addressed successfully.
The tunnel is equipped with variable traffic signs in order to ensure enhanced safety of the traffic, regulated from traffic control centres along the A1 motorway. Electronic equipment of the tunnel allows radio reception of two UHF radio frequencies (HR1 at 102.3 MHz and HR2 at 97.5 MHz) as well as use of cell phones. Electrical power is supplied to the tunnel through one 35 kV switching station at each end of the tunnel and 8 distribution switching stations in the tunnel itself. A backup electrical power supply is also provided to ensure continuous operation of the tunnel.
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