The S sets are a class of electric multiple units (EMU) that operated on Sydney's suburban rail network from 1972 up until 2019.

Originally entering service under the Public Transport Commission, the sets also operated under the State Rail Authority, CityRail and Sydney Trains.

[5] They were paired with 1965–67 Tulloch-built trailer carriages that had previously operated in company with single deck power cars.

These were all built to the Series 2 design with Budd type polished inserts on the carriage sides, flat rather than tapered number 2 ends, throw-over rather than sliding reversible seats, upgraded interior lights and a natural stainless steel finish.

[8][9] In April 1982, ten driving trailers were introduced on local services between Scarborough and Port Kembla.

[10] They were hauled by 48 class diesels but because of incompatibility between the electrical systems, the guard operated doors were disconnected.

[18] To operate services on the newly electrified Riverstone to Richmond line from August 1991, all 10 driving trailers and a number of Series 1 power cars were fitted with headlights.

Power cars received a destination indicator and had yellow applied to the lower half of their fronts.

This involved the removal of the yellow painted front (on some cars), pantograph and opening up of the driving compartment for passengers.

The last sets were transferred from Mortdale to Flemington in March 2013 bringing an end to their operation on Eastern Suburbs & Illawarra services.

[24] In June 2014, the government announced that all timetabled services except those on the T7 Olympic Park shuttle, would be operated by air-conditioned trains.

Six S sets were initially kept for emergencies but sufficient availabilities of other air-conditioned rolling stock ultimately deemed this redundant.

The remaining S sets were mostly phased out by the end of April 2019, with the introduction of an updated timetable of the Sydney Trains network.

On 27 June 2019, Transport Minister Andrew Constance joined Sydney Trains Chief Executive Howard Collins and rail employees on a farewell run from Central Station across the Sydney Harbour Bridge to Lavender Bay.

[28][29] The last timetabled S set service ran on the following night, on 28 June 2019, on the T7 Olympic Park Line.

[33] Beckhaus, John; Halgren, Stephen (2007), Sydney's Electric Trains, Australian Railway Historical Society NSW Division, ISBN 978-0-9757870-8-3