| Box Width: | auto |
| Lower Inn Valley Railway | |
| Other Name: | Bahnstrecke Kufstein–Innsbruck |
| Native Name: | Unterinntalbahn |
| Native Name Lang: | de |
| Type: | Heavy rail, Passenger/Freight rail Intercity rail, Regional rail, Commuter rail |
| Status: | Operational |
| Locale: | Tyrol |
| Start: | Border of Germany–Austria |
| End: | Innsbruck |
| Stations: | 21 |
| Open: | 24 November 1858 |
| Owner: | Austrian Federal Railways |
| Operator: | Austrian Federal Railways |
| Linelength Km: | 75.130 |
| Tracks: | Double track |
| Routenumber: | 300 Salzburg Hbf - Brennero/Brenner 301 Jenbach - Telfs-Pfaffenhofen / Steinach in Tirol |
| Linenumber: | 302 01 Border near Kufstein–Wörgl Hbf 101 04 Wörgl Hbf–Innsbruck 101 15 Beschleunigungsgleis Wörgl Hbf – Wörgl Kundl |
| Electrification: | 15 kV/16.7 Hz AC Overhead line |
| Speed Km/H: | 160 |
| Map State: | collapsed |
The Lower Inn Valley Railway (German: Unterinntalbahn) is a two-track, electrified railway line that is one of the major lines of the Austrian railways. It was originally opened as the k.k. Nordtiroler Staatsbahn (Imperial and Royal North Tyrolean State Railway). It begins at the German border near the Austrian city of Kufstein as a continuation of the Rosenheim–Kufstein line and runs in a generally south-westerly direction through Tyrol along the Inn valley to Innsbruck. The line is part of the Line 1 of Trans-European Transport Networks (TEN-T). The line is owned and operated by Austrian Federal Railways (ÖBB).
Emperor Franz Joseph I of Austria had ordered its construction in 1853. The line was the first railway in western Austria, opened on 24 November 1858.
See main article: New Lower Inn Valley railway. In order to increase the capacity of the track and in preparation for the construction of the Brenner Base Tunnel a new high-capacity line has been built between Kundl1 junction and Fritzen-Wattens 1 junction (at Baumkirchen). It was opened on 9 December 2012 for scheduled traffic. The great majority of this line has been built in tunnel in order not to increase noise pollution in the Inn valley. The new route is designed for mixed traffic up to 250km/h and is fitted with ETCS Level 2 signalling system.[1] [2] An extension of the new line from Kundl/Radfeld to Brannenburg is in the planning phase.