Melbourne City Loop (opened 1981)
Melbourne's suburban lines terminated at Flinders Street, a waterfront dead-end. An underground loop was first proposed in 1929, construction began in 1971, and the loop opened in stages from 1981 after decades of political wrangling.
Turned Melbourne's separate suburban lines into a connected system through the city centre.
The loop remains the core of Melbourne's suburban rail network today.
Auckland faced the identical dead-end terminus problem at Waitematā; the CRL is the through-link that makes the whole network function.
