The New South Wales Government Railways began planning the electrification of the Main Western line over the Blue Mountains from 1949, and with that plan in full swing by the early 1950s, called tenders for 80 cars, with the contract was awarded to Commonwealth Engineering, Granville in 1954. Electric traction equipment was supplied by the Metropolitan-Vickers, Manchester. However, before construction began the order was amended with the 20 planned first with buffet cars built as full first class seating cars, after a review of the New South Wales Government Railways conducted by American firm Ebasco Services Incorporated in the mid-1950s recommended the change. The U sets were a bit different compared to the suburban single decked trains that were delivered at the same time. They were the first EMUs in NSW to feature stainless-steel construction using technology from the Budd Company, improving train acceleration and giving the trains lower maintenance costs and a longer usable life.
Delivery
The U Sets started to be delivered from June 1957, and the first sets made their first public appearances that same year. The first appearance took place on 22 June 1957 when they were hauled by electric locomotive 4612 as part of the first train to travel on the newly electrified Blue Mountains line. Normal services began on 15 September 1958, and all were in service by March 1960. The cars were numbered as:
Second-class Motor Cars: CF 5001-40
Second-class Trailer Cars: TF 6001-20
First-class Trailer Cars: ETB 6021-40
First class travel was abolished on 1 September 1974. This saw the removal of the word "Second" on all carriages and also allowed non-first class passengers to enjoy the benefits of non-smoking carriages for the first time.
In service
The U sets initially entered service on the Main Western line to Bowenfels which was cut back to Lithgow in 1974. As the electrified network expanded they began to operate to Gosford, Wyong, Newcastle, Port Kembla and Dapto. The U sets were supplemented by V set double deck sets from 1970. From the mid 1970s many had their original lift-up windows replaced by Beclawat sliding windows.
Withdrawal and preservation
Withdrawal of the sets began in 1994 as new Tangara G sets began replacing them. The last U Sets were withdrawn in November 1996. A number of U Set carriages have been preserved and some are operational:. Most of the cars allocated to the Hunter Valley Railway Trust were scrapped in 2013, excepting CF 5001. Richmond Vale Railway lost cars TF 6001/02 and ETB 6026 in a bushfire in 2017.
Sydney Trains Heritage Collection - Redfern: CFs 5015, 5017, 5035, TF 6013 and ETB 6029
Sydney Electric Train Society: CFs 5001, 5003, 5021 & 5022, TF 6010 and ETB 6037. While not part of the official collection, SETS members also have CFs 5006 and 5010, TF 6006 and ETB 6038
Valley Heights Locomotive Depot Heritage Museum: ETB 6039
