Semmering Base Tunnel

Semmering Base Tunnel Semmering-Basistunnel
Northern tunnel portal at Gloggnitz (2019)
Overview
Status	under construction
Locale	Austria (Lower Austria, Styria)
Termini	Gloggnitz Mürzzuschlag
Website	German / English
Service
Type	High-speed rail Commuter rail Freight rail
Technical
Line length	27.3 km (17.0 mi)
Track gauge	1,435 mm (4 ft 8+1⁄2 in) standard gauge
Operating speed	230 km/h (145 mph)

The Semmering Base Tunnel is a railway tunnel under construction between Gloggnitz and Mürzzuschlag in Austria underneath the Semmering Pass.^[1] The existing route is 41 km long and the Semmering Base Tunnel will be 27.3 km long. The new route will offer time savings of up to 30 minutes, partly on account of the shorter route and partly on account of the higher speed limit (maximum 250 km/h)^{[citation needed]}.

Construction began on 25 April 2012 and the link is expected to enter operational service in 2030,^[2] delayed from the original estimate of 2026^{[citation needed]}. The main benefit of the new tunnel will be increased ease of use for freight traffic. The gradients of the traditional routes requires the use of two locomotives; the reduced gradient of the new link will enable the transit of freight traffic using just one locomotive. The SBT and the Koralm Railway in combination will enable freight transit across the whole southern line with just one locomotive.

Currently, the fastest Vienna-Graz and Vienna-Klagenfurt journeys on the Railjet services are 2 hours 35 minutes and 3 hours 55 minutes, respectively. The Koralmbahn will enable Graz-Klagenfurt journeys of approximately 45 minutes, as such it will bring Vienna-Klagenfurt journeys down to around 3 hours 25 minutes starting end of 2025. The SBT is projected to enable time savings of additional 45 minutes, which will enable journeys from Vienna to Graz and Klagenfurt of 1 hour 50 minutes and 2 hours 40 minutes, respectively.^[3]