Preserved 660 class railcar 661 is stabled at the Lithgow State Mine Railway alongside 4819 on 7-2-2017.
They were introduction from 1949 in 2 car sets as 600/700 cars to operate on branch lines .
between 1973 and 1975 , five 2 car sets were refurbished into 660/760 class sets finishing out thier days on Woolongong and Newcastle services before withdrawn in 1994