New South Wales Tulloch double deck carriage stock

In February 1964, the first of 120 double deck trailers was delivered by Tulloch Limited to the New South Wales Government Railways. These were purchased to replace wooden trailer carriage stock from Sydney's suburban fleet that had been converted for usage with the single deck Wooden motor cars in the early 1920s.^[2]

The first 40 were built with power operated doors to operate with the W set (Then S set) power cars, replacing the trailers (T4701-T4740), resulting in them being converted from powered to manual doors with the carriage numbers being increased by 50 making them T4751-T4790 and put into manual door suburban sets.^[3]

The remaining 80 were fitted with manually operated doors for operation with the Standard, Tulloch single deck, and even timber stock.^[2] These last 80 carriages built were placed in the manual doors sets based at Punchbowl and Mortdale after a series of trials to test the power of the older single deck motor cars.^[1]

Further carriages were converted to power door operation in 1972/73 to operate with the Series 1 double deck S set motor carriages. After the conversions were completed, T4801-T4833 formed part of the W sets, T4839-T4895 were part of the S sets and T4834-T4838 and T4896-T4920 were operated in manual door form with Suburban and single deck Tulloch stock.^[2][4]

Originally painted Tuscan red, from 1973 they were repainted in the Public Transport Commission blue and white livery, although this livery was applied differently on some carriages with the Riviera white stripe being painted on higher up on some carriages than others before the livery was changed to Indian red in 1976, but not all cars were repainted.^[2]

In 1992, T4812, T4816, T4830, and T4807 on set W1 were painted in the "Sesqui Train" livery in celebration of 150 years of the city of Sydney, and T4810, T4828, T4825, and T4820 on W2 were repainted in the "Zoo Train Mk2" livery in 1992 to advertise Taronga Zoo.^[3][5][6] In order to create a consistency with the stainless steel carriages they operated with, T4852 and T4867 were repainted in an experimental silver livery.

After a three-year lapse, T4872 was repainted flake grey, a livery that was gradually rolled out to the remaining Tulloch carriages in S sets with the last completed in June 1993.^[7] The interiors were painted in two-tone green, but some cars in S sets had their lower decks painted in flake grey and some in black.^[2] Some were refurbished in accordance with the CityDecker program being given white walls, blue seats and yellow passenger doors like the other S set cars.^[8][9]

Those operating in single deck sets were withdrawn by November 1993, while those in S sets remained in service until the end of March 2004, being replaced by the "Millennium" M sets built by Downer Rail in the late 1990s and early 2000s. As these last trailer cars were retired, 23 S set power cars were converted into trailers to fill the imbalance of power to trailer cars in the fleet.^[1] The vast majority of these carriages would be broken up for scrap in the years following.^[10][11]

In 1966, tenders were called for double deck power car prototypes to take advantage of the advances in electric carriage technology being made at the time. Tulloch Limited won the contract in 1967 and in mid to late 1968 would build four new prototype power cars numbered C3801-C3804 with the latter being the first one to be completed.^[1]

These power cars were put into a dividable eight car set with trailers T4839, T4840, T4843 and T4844 that was targeted "S10" following on from the Comeng single deck sets that were targeted S1-S9 in 1957. Originally, the set was to operate with trailers T4841-T4844, but T4841 and T4842 were replaced by T4839 and T4840 as the W sets could only operate with the latter two.^[2]

To operate with the four experimental double deck power cars, in 1968, trailers T4843 and T4844 were converted for powered door operation before the experimental consist underwent trials for testing and repair.^[1][2]

Set S10 (C3801, T4839, T4840, C3802, C3803, T4843, T4844 and C3804) entered revenue earning service on 6 January 1969, with the set gaining itself the nickname "The Flying Nun" by the rail circles.^[1][12]

S10 proved unreliable as the train broke down regularly. A problem which was worsened by all four power cars having electrical systems coming from different manufacturers. The less than adequate reliability of the experimental power cars incentivized substitution with the more standardized W set motor cars.^[13]

In spite of these problems, the train was considered successful enough that all trains built following would be of double deck design with 53 new motor cars (C3805-C3857) built by Comeng in the early 1970s continuing from the numbers of the Tulloch motor carriages, and cars C3805 and C3806 were placed into set "S11" following on from the targeting of the experimental S10 set.^[1][14][15]

Due to the non-standard nature of their electrical systems, following the withdrawal and disbandment of the S10 consist, three of the four power cars were to be converted into trailer cars.^[16] This would involve the removal of most of the electrical equipment including driver's controls, and pantographs with all cars sent for conversion at the Electric car workshops in Chullora.^[1][17]

One of these motor carriages, C3801 was first stored at Punchbowl until 1977 before it was transferred with the other three and would have its electrical equipment removed in 1978, before returning to active service, renumbered as T4797 in 1980, followed by C3803, as it had its electrical equipment removed in the same year before re-entering service under the new number T4799 in 1982 with the cab converted for seating of 16 passengers as well as the crew doors sealed off with panels.^[1]

While C3802 was also set to be converted into a trailer car and be renumbered as T4798, this process was never finished as its brakes where adjusted poorly and would apply too early, wearing them out quickly.^[16][17] Despite being partly converted, it was scrapped in 1990 before it could re-enter service.^[1][18] T4797 would serve in its converted state until withdrawal in 1982 and was cut up in 1991 at Chullora, while T4799 remained in service until the early 2000s. C3804 remained at the Elcar works on a plinth until its closure in 1994.^[1]

All four motor cars were outshopped in Tuscan red with all except C3804 later being painted in the Public Transport Commission blue and white livery. As trailer cars, T4797 and T4799 entered service in an Indian red livery, With T4799 later being repainted silver and eventually flake grey.^[7][1]