AGC to revitalise regional routes

LAST MONTH was due to see the first series-built dual-mode Autorail à Grande Capacité delivered to Midi-Pyrénées region, following the roll-out of six prototypes during 2003. Over the next two years deliveries are due to ramp up to nine units a month, with 279 sets to be completed by the end of 2007.

In the late 1990s SNCF identified a need to replace 30-year-old DMUs and EMUs which would soon be life-expired. Tenders for the AGC concept were invited in August 2000, with SNCF looking to order units with a high degree of commonality to reduce development costs and simplify commissioning. Feedback from regional authorities responsible for specifying and funding local rail services included requirements such as low floors, wide gangways and disabled accessibility.

Bombardier put forward proposals for a unified family of electric and diesel units, together for an option for a dual-mode variant which SNCF was considering but had not specified. These would be equipped with a diesel engine but also capable of operating as EMUs when running on electrified lines. Commonality of 90% of the parts between diesel and electric units would reduce the cost of spare parts, training, servicing and maintenance, offering savings estimated at 5% of the vehicle cost.

On December 13 2001 SNCF President Louis Gallois signed a €1·65bn framework contract with Bombardier for delivery of up to 500 AGC sets. This included an initial firm order for 192 sets worth €700m to be built at Crespin for delivery from 2004. Subsequent orders brought the total up to 279 units by the end of 2003, with a further 45 to be confirmed shortly. The price of around €1m per car is about half that paid by SNCF for previous generations of TER DMUs ordered in the mid-1990s.

Emphasis on modularity

The AGC trainsets are designed as modular articulated units, with two basic bodyshells: a powered driving car and one or two unpowered intermediate sections with a low floor 590mm above rail. The floor level is ramped up at the car ends to pass over the unpowered articulation bogies. A single 1300mm wide doorway is provided in the centre of each car.

Each driving car has a high-floor section behind the cab, leaving room for a powered bogie and an underfloor diesel engine or transformer. One or both driving cars can be powered, depending on the configuration. A 12-cylinder MAN 2842 LE606 diesel engine is used, rated at 662 kW at 2100rev/min.

Minimum length is a two-car set, with just one motored bogie (Table I), but as yet no region has ordered any two-car sets. Most are expected to redeploy existing units cascaded from other routes by the arrival of three and four-car sets.

To maximise interchangeability, an electric transmission is used for all variants. This is rated at 1·8MW to suit the EMU version. Fitting the DMUs with mechanical transmissions would have added complexity, and probably required the fitting of additional power packs with their associated costs. The diesel engine drives an alternator which supplies 1·5 kV to a standard converter pack. This in turn feeds three-phase traction motors on both axles of the adjacent bogie.

The input voltage for the transmission was selected to suit operation on 1·5 kV DC electrified routes - this capability is provided for all EMU and dual-mode versions. The pure EMUs have an underfloor 25 kV transformer in the place of one diesel engine to give network-wide availability. Bombardier is also offering a tri-mode version with diesel, 1·5 kV and 25 kV capability, but as yet no-one has ordered it. The company has also been asked to look at adding 15 kV 16 2/3 Hz and 3 kV DC for possible cross-border operation into Germany, Switzerland, Belgium and Italy.

As well as offering lower operating costs when running in electric mode, the dual-mode trains are expected to improve fleet availability and flexibility of deployment, reducing the number of spare trainsets required. This was reflected in the early orders, as almost half of the diesel trainsets ordered by October 2003 were dual-mode.

Bombardier also believes that an electric transmission will provide a smoother ride when operating in multiple, along with lower maintenance costs. Electric braking will reduce wear and tear on the air-operated disc brakes, and inverter wheelslip control will minimise the risk of wheel damage.

Regenerative braking will also help to reduce energy use, with recovered energy stored in on-board batteries designed for 500000 cycles, or around 15 years of normal service use. On a typical 140 km/h line with stations 8 km apart, the manufacturer believes that energy savings will total around 30%. Stored energy will be reused during acceleration, boosting the diesel engine's output by up to 80%. This will allow the three-car AGC to be extended to four-car in future with only a minimal loss of performance.

The on-board battery can also be used to move the trains at low speed in depots, saving the need to start up the diesel engines and remove the exhaust gases from workshop buildings. Dual-mode vehicles will be able to operate through services between electrified and non-electrified lines, eliminating changes and improving the quality of regional services.

The modular design also allows the interior configurations to be varied to meet local requirements. Bombardier is offering two main options, designated Intercités and Grand Confort. Seating is a mix of face-to-back and groups of four around tables. Seats are arranged 2+2 throughout, except for 2+1 in the first-class on Intercités sets only.

One disabled-accessible toilet is fitted in each trainset, where accommodation for two wheelchair users is also provided. A smaller second toilet is also fitted in the longer units. A multi-function space in one driving car can be fitted out to carry luggage, bicycles, ski racks or a small buffet as required. Internal video surveillance is available as an option with both interior types, and has been adopted by seven regions so far.

Delivery progress

The first dual-mode prototype was dispatched from Crespin in July 2003 and began trials on the SNCF network in September, initially only using its diesel capability. Following tests at up to 158 km/h between Rennes and Brest, the unit was transferred to SNCF's Lannion - Plouaret line for shakedown running. Testing on 1·5 kV electrified routes is scheduled to start in mid-2004.

Second to be completed was a three-car DMU, which was tested at Valenciennes and demonstrated to SNCF President Louis Gallois and other VIPs in October (RG 11.03 p697). The other four prototypes are also straight DMUs, and one of these was sent to Wien for testing in the climate chamber.

Initial series deliveries are expected to start with one unit for each region, to allow local route testing and the start of crew training. These will then be followed by series fleets of diesel and dual-mode units as production rates step up through the course of this year. The first EMU version is not expected to roll out until the beginning of 2005.

• CAPTION: Initial testing and commissioning with one of the four pre-series diesel units took place at the Valenciennes test track
• CAPTION: SNCF President Louis Gallois and guests from the purchasing regions participated in ceremonies to unveil the AGC family on October 9 last year. This included a tour of Bombardier's Crespin plant and a ride on the second diesel-engined prototype unit at the Valenciennes test track

Table I. AGC technical details

Table II. Confirmed AGC orders