SNCF Class BB 36000

SNCF Class BB 36000

Company type	Electric locomotive
Industry	Rail transport
Predecessor	SNCF Class BB 26000 (partial order)
Founded	1996
Founder	GEC-Alsthom (later Alstom)
Successor	SNCF Class BB 36200 and BB 36300 (subclasses)
Headquarters	France
Area served	France, Belgium, Italy
Products	Multi-system electric locomotives
Owner	SNCF

The SNCF Class BB 36000 locomotives, known under the trade name Astride, constitute a fleet of four-axle, twin-bogie electric engines capable of operating on three different voltage systems. These units were manufactured by GEC-Alsthom (which later became Alstom) between 1996 and 2001 specifically for SNCF.

In total, sixty locomotives were built, with thirty subsequently converted into the subclasses 36200, and 36300. These upgraded variants feature advanced safety equipment to facilitate cross-border services between France and Italy. By 2012, the fleet was divided evenly between 30 original BB 36000 machines and 30 BB 36300 models, the latter being classified in Italy as FS Class E436.

Locomotives numbered from 36001 to 36030 mainly operate freight services along French-Belgian corridors, playing a key role in international cargo transport.

Background and design

The initial batch of 30 Class BB 36000 units emerged from an adaptation of a larger order for 264 dual-voltage SNCF Class BB 26000 (Sybic) locomotives. Ultimately, 234 Sybics were produced, while the final thirty were designed as triple-voltage machines. These featured the ability to run under 3 kV DC using AC induction motors combined with modern GTO semiconductor technology. This tri-system capability was introduced to meet the growing demand for cross-border rail traffic in line with European Union freight corridor strategies. The locomotives maintain stable traction performance across electrical supplies of 25 kV AC and both 3 kV and 1.5 kV DC. Their design complies with EN 50121 standards for electromagnetic compatibility and incorporates regenerative braking for improved energy efficiency. Other technical highlights include water-cooled power electronics, partial system redundancy to enhance reliability, and ease of maintenance.

The name Astride derives from Asynchrone Tri-system Drive Engine, while the external styling was developed by MDB Design.

When powered by a 25 kV AC supply, a 5.76 MW transformer feeds four secondary windings at 1450 V AC. This voltage is rectified using switched power electronics that employ pulse-width modulation at approximately 300 Hz to regulate output voltage. The resulting current feeds a 2.8 kV intermediate DC link which supplies four inverters, each controlling one traction motor.

For DC operation, two independent 2.8 kV DC links serve pairs of inverters per bogie. At 1.5 kV DC, voltage is boosted to 2.8 kV via choppers; under 3 kV DC supply, the circuitry is adjusted accordingly.

Each of the four traction motors is a force-cooled three-phase induction motor rated at 2070 V and 600 A, weighing around 2.55 tonnes with integrated reduction gearing mounted on the bogies. Every motor is controlled by its own inverter. Dynamic rheostatic braking dissipates energy through electronically managed resistors, delivering up to 130 kN braking force within the speed range of 30–80 km/h; above this threshold, electric braking power is limited to 2.96 MW. Regenerative braking is enabled when operating under the 25 kV AC system.

Auxiliary power is provided through a step-down chopper feeding a 525 V DC network supported by four three-phase inverters rated at 75 kW each. These manage variable-speed cooling fans and fixed-frequency equipment such as compressors and pumps, with built-in redundancy for increased reliability. Additionally, two inverters at 72 V handle battery charging functions.

Subclasses and operations

Beyond the modified Sybic order, SNCF commissioned an extra thirty units, resulting in a total delivery of sixty locomotives between 1997 and 2002 numbered BB36001 through BB36060. The first thirty units (BB36001–BB36030) were painted red and primarily allocated to routes serving Belgium, whereas the remaining thirty featured a green freight livery intended for Italian-bound trains. During this period, comparable models—the SNCB Class 13 and CFL Class 3000—were also produced for Belgium and Luxembourg respectively.

These locomotives were originally conceived as versatile units suitable for both passenger and freight duties and were initially planned for use on the now-cancelled Nightstar cross-channel sleeper services. In July 2010, locomotives numbered from 36001 to 36030 were transferred to SNCF's leasing division Akiem.

France-Italy

Starting in 2003, adaptations allowed these locomotives to operate within Italy, resulting in two distinct variants: the BB36200 subclass, comprising 12 units designed for multiple unit control and equipped with fire suppression systems, and the BB36300 subclass, consisting of 8 units that incorporated the SAFI safety mechanism. Eventually, all BB36200 locomotives along with units numbered 36051 to 36060 were upgraded to meet the BB36300 specifications.

Since 2003, Astride locomotives have been tasked with hauling rolling road trains managed by AFA Autostrada Ferroviaria Alpina, a subsidiary of Trenitalia/SNCF Geodis, along the route between Aiton, Savoie and Orbassano, Italy, utilizing specialized Modalohr wagons. Although operational challenges have been noted—such as an availability rate of 80% and an incident frequency of 23 per million kilometers recorded in 2005—these locomotives continue to play a crucial role in this transportation service. For AFA operations, Trenitalia procured units numbered 36339 and 36348.

Locomotives assigned to Monferail, SNCF Fret’s Italian division, were renumbered under the Italian system as E 436.

See also

• SNCB Class 13 from Belgian Railways and CFL Class 3000 of Luxembourg Railways share bogies, chassis, and mechanical components with the BB 36000 series.
• The electrical systems employed in the Astride class have been adapted for use in HHP-8 locomotives.
• Modalohr

Sources

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