North Queensland 's first hydro electric plant was built in 1933 to power the 13 acres ( 5.3 ha ) park .
The castle grounds were ready to welcome the public in 1935 .
North Queensland 's first hydro electric plant was built in 1933 to power the 13 acres ( 5.3 ha ) park , and the castle grounds were ready to welcome the public in 1935 .