The Railway Archives has a large collection of maps and diagrams of the railways in Australia, both current and historical. A selection is available here.

Current Maps
New South Wales
Sydney
Victoria and Melbourne – Train Map September 2023
Victorian train network Sep 2023
Melbourne – Tram Map September 2023
Melbourne Tram Network Sep 2023

Queensland

Brisbane
South Australia
Adelaide
Tasmania
Hobart
Western Australia
Perth

Historic Railway Maps

Aust 1940
Digest NSW
queensland 1968
Victoria Map 1932
NSW diagram map
WAGR 1939
tas
South Australia Map 1937
VR_Suburban_map_1965