Australian Rail Track Corporation (ARTC) has completed the upgrade of the rail line between Casino and Grafton.
The upgrade involved removing 100km of signalling at the northern rail link, which employed redundant open wire line route signal technology.
The upgrades are expected to improve reliability, reduce signal failures and increase line capacity.
ARTC CEO David Marchant said the ongoing upgrades are part of the north-south strategy to cut the transit time from Melbourne to Sydney to 10h 40min and from Sydney and Brisbane to 15h 35min.