Germany has a surprisingly large amount of routes capable of operating tilting trains, but sadly many of them don't have any tilting services at all and are instead operated with "standard" material.
According to DB, the following lines are currently equipped with the GNT train protection system for tilting trains:
KBS 330: Halle (Saale) Hbf - Ilsenburg (121,8 km, diesel)
KBS 430: Benhausen - Vellmar-Obervellmar (94.3 km, electrified)
KBS 510: Dresden-Altstadt - Chemnitz Hbf (77.4 km, electrified) and Chemnitz-Mitte - Hof Hbf (142 km, electrified)
KBS 525: Leipzig-Holzhausen - Chemnitz Hbf (70.9 km, diesel)
KBS 540: Gera-Debschwitz - Gößnitz (33.1 km, diesel) and Gößnitz - Glauchau-Schönbörnchen (12.4 km, electrified)
KBS 560: Abzw. Saaleck - Saalfeld (75.4 km, electrified)
KBS 565: Weimar - Jena West (22.6 km, diesel) and Jena-Göschwitz - Gera Hbf (40.5 km, diesel)
KBS 570/815: Neudietendorf - Schweinfurt Hbf (145.5 km, diesel)
KBS 580: Erfurt - Bad Sulza (47.7 km, electrified)
KBS 582: Leipzig-Leutzsch - Leißling (38.8 km, electrified)
KBS 604: Bufleben - Leinefelde (59.8 km, diesel)
KBS 605: Eisenach-Stedtfeld - Wildeck-Obersuhl (22.6 km, electrified), Abzw Faßdorf - Abzw Bebra-Blankenheim (4.9 km, electrified) and Abzw Faßdorf - Bebra (4 km, electrified)
KBS 610: Fulda - Abzw Bebra-Blankenheim (52.9 km, electrified), Bebra - Kassel Wilhelmshöhe (54.2 km, electrified)
KBS 615: Frankfurt (Main) Abzw Main-Neckar-Brücke - Hanau Hbf (21.5 km, electrified) and Haitz-Höchst - Flieden (38 km, electrified)
KBS 670: Neustadt (Weinstr) Hbf - Saarbrücken Hbf (99.8 km, electrified)
KBS 730: Basel Bad Bf - Lauchringen West (63.1 km, diesel) and Beringen Bad Bf - Singen (Hohentwiel) (26.3 km, electrified)
KBS 731: Radolfzell - Lindau-Aeschach (81.7 km, diesel)
KBS 740: Stuttgart Hbf- Singen (Hohentwiel) (173.8 km, electrified)
KBS 743: Inzigkofen - Thiergarten (Hohenenz) (6.6 km, diesel)
KBS 750: Stuttgart Hbf - Plochingen (22.8 km, electrified)
KBS 760: Plochingen - Tübingen Hbf (48.8 km, electrified)
KBS 755: Ulm Hbf - Ast Unlingen (61.7 km, diesel) and Riedlingen - Sigmaringen (27.4 km, diesel)
KBS 757: Ulm Hbf - Aalen (72.5 km, diesel)
KBS 766: Tübingen Hbf - Sigmaringen (87.5 km, diesel)
KBS 800: Aschaffenburg Hbf - Abzw. Nantenbach (42.5 km, electrified)
KBS 805: Fürth Hbf - Neustadt (Aisch) (33.3 km, electrified) and Würzburg Hbf - Iphofen (32.5 km, electrified)
KBS 810: Würzburg Hbf - Schweinfurt Hbf (43.4 km, electrified)
KBS 820: Fürth Hbf - Forchheim (Oberfr) (30.7 km, electrified)
KBS 840: Lichtenfels - Saalfeld (87.8 km, electrified)
KBS 850: Hof Hbf - Hochstadt-Marktzeuln (87 km, diesel)
KBS 855: Regensburg Hbf - Oberkotzau (173.6 km, diesel)
KBS 860: Nürnberg Hbf- Schnabelwaid - Marktredwitz/Neuenmarkt-Wirsberg (163.4 km, diesel)
KBS 870: Hersbruck (rechts Pegnitz) - Neukirchen - Weiden (Oberpf)/Irrenlohe (113.9 km, diesel)
KBS 875: Schwandorf - Furth im Wald (67.2 km, diesel)
KBS 880: Abzw Nürnberg Reichswald - Regensburg Hbf (91.1 km, electrified), Obertraubling - Radldorf (23.4 km, electrified) and Straßkirchen - Passau Hbf (64.8 km, electrified)
KBS 910: Nürnberg Hbf - Bäumenheim (101.2 km, electrified)
KBS 970: Kaufbeuren - Lindau Hbf (132.6 km, diesel)
KBS 971: Augsburg Morellstraße - Buchloe (38.6 km, diesel)
In addition, according to other sources, the following lines are (or were?) capable of tilting operations but are - apparently - not equipped with the GNT system. Maybe another user can shed some light on these:
KBS 208/225/240: short stretch between Coswig and Abzw. Leckwitz
KBS 320/330: Hildesheim Hbf - Goslar - Vienenburg
KBS 474: Euskirchen - Trier
KBS 625: Koblenz Hbf - Gießen
KBS 665.3-4: Schifferstadt - Germersheim
KBS 676: Neustadt (Weinstr) - Winden (Pfalz) and Wörth - Karlsruhe Hbf
KBS 680: Gau-Algesheim - Saarbrücken Hbf
KBS 685: Trier Hbf - Saarbrücken Hbf
KBS 704: Germersheim - Graben-Neudorf