 By 1928, twelve return passenger services also ran on the line per week, with a journey time from Flinders Street station to Wonthaggi taking approximately four hours.The introduction of diesel rail motors in the 1950s saw a reduction in journey times for passenger services on the line to around three hours by 1954, but service frequency was now eleven return passenger services operating per week.The conversion of Victorian Railways from steam to diesel-electric power during the 1950s and 1960s reduced demand for black coal and in 1968 the mine closed.