However, funding was limited in the 1930s due to a combination of a tight fiscal policy under Prime Minister Osachi Hamaguchi during the Great Depression, and a number of technical issues.

The projected route of the Itō line along the mountainous east coast of the Izu Peninsula required numerous tunnels and bridges.

Workers digging a tunnel near Usami encountered problems with underground hot springs, similar to that experienced in the construction of the Tanna Tunnel, which had recently been completed years later than originally projected and far over budget.

On March 30, 1935, the initial 8.7 km section of the Itō Line linking Atami with Ajiro was opened.

Further work was delayed, and then canceled due to the outbreak of World War II.