The Richmond Line had been partly electrified through to Riverstone in 1975, and was finally electrified all the way to the terminus at Richmond in 1991. This completed the electrification of the suburban Cityrail network that had begun when Bradfield built the underground city subways in the 1920s and the Sydney Harbour Bridge in the 1930s. The opening of the newly electrified line was covered by Nine News on the day, video ois included below.
Despite being electrified, the line remained single track. Back in 1991 it shared this dubious claim with the Carlingford and Cronulla Lines. Since then the Cronulla Line has been fully duplicated and the Richmond Line partly duplicated (through to Schofields as of 2011). Riverstone, Mulgrave and Richmond Stations have 2 platforms, which act as passing loops to allow trains to travel in both directions despite there being only a single track. However, the large amount of single track remaining on the line means that the Richmond Line remains limited to only 2 trains per hour through to the Richmond Station terminus.