The Desiro family keeps growing

THE FIRST Desiro EMU for Slovenian Railways has begun trials at the Wildenrath test centre of Siemens Transportation Systems. Deliveries to SZ are expected to start next month, with a total of 30 Desiros being built by Siemens and TVT of Slovenia for service on the 85 km Koper - Postojna route as well as between Ljubljana and Zidani Most (62 km).

Siemens is currently delivering 150 VT642 DMUs to German Railway, and examples of the first Desiro build are undergoing commissioning trials at Wildenrath. The modular Desiro family is based on an aluminium bodyshell, which in the case of the DB and SZ builds has a lowered boarding section with a floor height of 575mm. The monocoque cab sections are manufactured separately in glass-reinforced plastic and then bonded to the bodyshell.

Powered and trailer bogies for the articulated Desiro family are to the same basic design, a member of the SF5000 family developed by Siemens' Austrian subsidiary SGP. Steel coil springs with rubber isolation form the primary suspension, with secondary suspension provided by air bags.

Both EMU builds for SZ have the outer bogies powered, with a starting tractive effort of 100 kN for the Class 312/0 and 120 kN for the Class 312/1. The Desiro traction package features three-phase traction motors, and both SZ builds have a maximum acceleration of 1m/s2.

Traction equipment has been configured as two independent lines each having their own pantograph, with traction and auxiliary converters taking power directly from the overhead line at 3 kV DC. Air-cooled GTO converters installed underfloor feed the traction motors, and the EMUs are equipped for regenerative braking. All Desiro builds feature the Sibas¨32 control and diagnostic system.

The order from Hellenic Railways Organisation also involves a technology transfer arrangement, with 20 five-car EMUs to be built by a consortium of Siemens and Hellenic Shipyards. Deliveries are due to begin next year for deployment on the Athens - Thessaloniki main line. Sharing with the SZ build air-conditioning, fully-accessible controlled-emission toilets and passenger information displays, the OSE Desiros will have a floor height for boarding of 800mm. There is an option for the third car to be fitted with a bistro counter.

Taking power at 25 kV 50Hz AC, the OSE Desiro will have a starting tractive effort of 210 kN and a maximum acceleration of 1m/s2. With traction equipment again configured as two separate lines, power is fed to an oil-cooled transformer installed under the floor of each end car. Air-cooled IGBT traction converters are installed under the end cars, supplying three-phase asynchronous motors. The OSE Desiro is also equipped for regenerative braking and has a Bo-2-Bo-Bo-2-Bo wheel arrangement.

British cousins

For the British market, Siemens has developed the Desiro UK based on a 20m aluminium bodyshell with a uniform floor height of 1157mm. Although riding on SF5000 bogies, the Desiro UK will not be articulated like the Desiro builds for DB, OSE and SZ. Siemens is offering three and four-car Desiro UK EMUs, both with two Bo-Bo power cars, for 750V DC third rail, 25 kV 50Hz AC or dual-voltage operation. A two-car EMU with a single power car is also proposed for 750V DC.

Rolling stock leasing company Angel Trains has placed two orders for four-car dual-voltage trains with through gangways. A speculative order worth £90m for 25 trains was announced on May 24 this year (RG 6.00 p344), and on July 11 First Great Eastern confirmed that it will lease 21 EMUs under a deal worth £75m.

On the dual-voltage four-car Desiro UK, one trailer car carries the pantograph and transformer, and each power car has an IGBT traction converter as well as shoes on the outer bogie to collect current at 750V DC. The traction converter has input/precharging circuits for both AC and DC, a four-quadrant controller for AC operation, a braking chopper for DC operation and a pulse width modulation converter identical for both line voltages. Each power car has four Siemens 1TB2 asynchronous traction motors. The traction package has been designed for uprating to 1730 kW, and simple conversion from AC to DC or dual-voltage operation.

The Duewag plant in Krefeld is due this month to begin assembling the first Desiro UK bodyshell, due for completion in February next year. In August 2001 the first complete train of the speculative order is expected to arrive at Wildenrath. Testing may involve the installation of reed track circuits and fitting a third rail to the main 6 km test circuit.

The first Desiro UK is expected to arrive in Britain in December 2001 and enter service in the summer of 2002. To meet this schedule, Siemens would ideally need to finalise the interior design with the eventual (and as yet unknown) operator by the end of this year. The 21 sets for First Great Eastern are due to be delivered during the summer of 2002.

British train operators are legally required to withdraw all MkI rolling stock by December 31 2002, unless it has received modifications to improve crashworthiness when an extension until December 31 2004 is permitted. Some 1500 MkI EMU cars are in operation, and Siemens is confident it would be able to have over 300 Desiro UK cars in service by the end of 2002 if an order is forthcoming by the end of this year.

Desiro UK for Angel Trains

Formation M+T+T+M

Length, mm 81356

Width, mm 2796

No of seats 280

No of standees at 4 pass/m2 150

Power supply 25 kV 50Hz AC/750V DC

Rating, kW 1550/1500

Maximum acceleration 1m/s2

Maximum speed 150 km/h