Kaldrma (Serbian Cyrillic: Калдрма)[1] is a village located in the Gračac municipality within the Zadar County in Croatia.

The so-called Steinbeiss Railway, built mainly to service the fledgling timber industry, branched off past Drvar, further to Jajce and Prijedor.

After WWII, in 1948 the Knin-Kaldrma section was upgraded to a normal gauge in order to become a part of a new Una railway, an important rail link between Zagreb and Dalmatia.

Traffic on Una railway was only sporadic during the Croatian War of Independence (1991–1995) due to the breakaway Serb Krajina blockade.

After 1995, traffic was not reintroduced due to the damage and difficulties concerning numerous border crossings on the line.