Gmunden
Graz
Innsbruck
Linz
Mölltaler
Pitztaler Glacier
Postlingberg
Salzburg
Serfaus
Vienna (Wien)

Pitztaler Glacier
glacier subway
 
Yes, glacier subways are becoming more popular and there are several of them in the world: including the Serfaus dorfbahn (village train) which may or may not be an actual \glacier subway, the Alpine Metro (Saas Fe, Switzerland), and the 3.2 km Pitztaler Glacier Express which was built in 1983.

Honorable mention: the Kaprun Gletscherbahn, now closed, where a fire in the tunnel claimed 155 victims.

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