In service

Following the successful trial of four double-deck power cars built by Tulloch in 1968, 53 Series 1 power cars were ordered from Comeng and delivered in 1972–73.^[3] They were paired with 1965–67 Tulloch-built trailer carriages that had previously operated in company with single deck power cars. The first 39 were painted tuscan to match the trailer cars while the last 14 were painted in the newly introduced Public Transport Commission blue and white livery.

From 1976, the blue and white livery was replaced by an Indian red livery. In 1979, painted Series 1 cars began to have their paint removed to match the Series 2 cars. Only seven were completed, and it wasn't until August 1988 that the program recommenced with the last carriage treated in 1990.^[4][5]

Subsequent orders saw another 154 power cars, 67 trailer cars and 85 driving trailer cars built by Comeng. 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.^[3]

A further order saw 80 power cars and 70 trailer cars constructed by A Goninan & Co in 1978–80. These cars differed in having a squarer type of fluting and flat fronts on the power cars.

All were formed into either four-car S sets or two-car T sets. In practice, there were only a few diagrams requiring two carriage sets resulting in most T sets being used to form six and eight-car sets. By the early 1980s, some permanent six-car sets had been formed and targeted as R sets. In December 1983 there were 60 T sets, 12 months later this was down to 19.^[6][7]

In April 1982, ten driving trailers were introduced on local services between Scarborough and Port Kembla. These two car PK sets ran until the line was electrified in December 1985.^[8] They were hauled by 48 class diesels but because of incompatibility between the electrical systems, the guard operated doors were disconnected.

From June 1984, four three-car sets of Goninan stock operated suburban services from Newcastle to Fassifern and Morisset as NC sets.^[9] This stock was allocated to Mortdale and periodically rotated. In August 1989, this was reduced to two sets.^[10] In September 1989, the remaining NC sets were replaced by two carriage L sets from Hornsby.^[11] These were replaced in January 1992.^[12]

In May 1987, the ten newest driving trailers based at Hornsby were renumbered D4001–D4010 and the remainder began to have their control equipment removed and revert to ordinary trailers.^[13] To allow the Tangaras to be targeted as T sets, the remaining two-car sets became L sets in April 1988.^[14][15] When refurbished in the 1990s the crew compartments were removed.^[16]

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.^[17]

From October 1996, two-car L sets replaced U sets on suburban services between Thirroul, Port Kembla and Kiama.^[18] These were later extended to three cars before being replaced by Tangaras in October 2011.

During the 1990s, all carriages were refurbished as part of the CityDecker program. This saw the interiors refurbished with white walls and ceilings, grey floors and blue seats. Power cars received a destination indicator and had yellow applied to the lower half of their fronts. Sliding Beclawat windows were replaced with hopper windows and doors painted yellow.

Replacement

After nearly 40 years of service, the Tulloch trailers were deemed life expired and the last withdrawn in March 2004. This resulted in a disproportionate number of power cars. To address the balance, 23 Comeng power cars were converted into trailers. Most of the conversions were Series 1 cars, however a few conversions involved Series 2 cars. This involved the removal of the yellow painted front (on some cars), pantograph and opening up of the driving compartment for passengers. Some cars had their external lights removed and plated over, and their cabs removed, other retained these fittings. All retained their motors and compressors for ballast purposes. The destination indicators were also retained as it would have cost too much to have them removed; they were painted over instead. These cars are easy to recognise as they have an open space where the pantograph once was.

During their history, S sets operated on all Sydney lines. The last six car R sets were deemed life expired in August 2012, with all carriages formed into four car S sets (which were typically operated in pairs). The last sets were transferred from Mortdale to Flemington in March 2013 bringing an end to their operation on Eastern Suburbs & Illawarra services. However, one set remained operational through parts of March and April on the line. In May 2014, all Hornsby sets were transferred to Flemington.

All remaining 498 carriages were to be replaced by A sets from 2012, with the last scheduled for replacement in 2015.^[19] In March 2013, it was revealed that forty eight S sets would need to be retained after the full introduction of the A sets, as the option to build further A sets had lapsed, meaning no trains had been ordered for the South West Rail Link.^[20] The last Series 1 power car was withdrawn in January 2014. The final A set was delivered in June 2014.^[21] Following the delivery of the final A sets, Sydney Trains retained 48 four-car sets (192 carriages).^[22]

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.^[21] With the introduction of a new timetable in November 2017, 40 four car sets were temporarily required to operate the weekday service, while the B sets were delivered. This meant that S sets would once again be scheduled to operate services on all lines in Sector 2.