INTRO: From 2001 commuters in Australia’s largest city are set to benefit from a fleet of 20 double-deck trains to be built and maintained by Clyde Engineering. These fourth generation Millennium trains will continue the progress achieved by the Tangara fleet, with the latest traction equipment

BYLINE: Colin F G Butcher*

Director,ACB Consulting Services

AT AN EARLY morning ceremony on October 8 1998 New South Wales Minister of Transport Carl Scully signed a contract for a new series of double-deck trains for Sydney. The first is scheduled to be delivered early in 2001 and will replace some of the earliest double-deck cars still operating suburban services.

The initial contract between the State Rail Authority and Clyde Engineering is for 20 sets of four cars. Maintenance of the trains for the first 15 years of operation is included in the contract, and the total net present value of the deal is estimated at A$300m. The contract includes options for up to 50 more sets and for the maintenance period to be extended up to a total of 35 years.

In many ways the contract represents a complete change for the SRA and for local industry. The contractor, Clyde Engineering, is to adopt systems engineering principles to design the trains in accordance with a performance specification. Payment for the trains will only be made after each set has been delivered and has passed the acceptance tests.

Four generations

The first generation electric trains for the Sydney suburban system were conventional single-deck units with red painted steel bodies. Motor and trailer cars were coupled to form sets of four, and two sets ran in multiple to form the longest trains for peak hour services. The Sydney suburban network is electrified at 1·5 kVDC (not as stated in RG 11.98), and as electrification expanded to the limits of the suburban area, journey times grew and greater comfort became a priority.

To provide more seating capacity, the SRA purchased 120 double-deck trailers in the early 1960s. These had a steel underframe with an aluminium superstructure and were painted to match the single-deck cars. These were the first cars to be fitted with air spring suspension, and this became a standard requirement for all future passenger cars for NSW. Most of these cars replaced one of the single-deck cars in a first generation set, and they were soon a common sight throughout the Sydney area.

In 1964 a prototype double-deck multiple-unit proved the viability of this form of suburban train, and no single-deck electric car has been purchased since the late 1960s. All the double deck trains that entered service after 1970 have stainless steel bodies with a corrugated outer skin, and these are known as the second generation suburban trains. Most have conventional resistance starting control, but some of the most recent units were fitted with chopper control and a number were air-conditioned.

In the early 1980s the SRA invited bids for a new series of double-deck trains and subsequently ordered the Tangara fleet. These third generation units use the same traction technology as the later second generation trains, and the arrangement of equipment is also much the same. However, they introduced a major change in styling with a smooth stainless steel exterior, skirts over the bogies, curved glass in the upper deck and plug doors.

As the Tangaras were delivered, the ’Red Rattlers’ were retired, and all the fleet became double-deck. About 55% of the suburban fleet of over 1200 cars is air-conditioned, and only a few of the earliest double-deck trailer cars are still in service.

Millennium trains

To provide extra capacity to cope with slow but steady growth, CityRail obtained government approval to purchase some new trains. These fourth generation suburban cars will displace the oldest double-deckers. They will be similar in size and general arrangement to most of the existing fleet with a driving trailer at each end, and two centre motor cars (Fig 1). As the high voltage equipment is spread over both types of car, sets are semi-permanently coupled by rigid drawbars. Two units in multiple will occupy the full platform length at most stations, so sets of more or longer cars would not match the infrastructure.

Some significant improvements in performance and advances in technology will be incorporated, including: