SNCF Class BB 900
| Company type | Electric locomotive class |
|---|---|
| Industry | Rail transport |
| Predecessor | Midi Class E4700 |
| Founded | 1936 |
| Headquarters | France |
Area served | Paris–Le Mans route, France |
| Products | Electric locomotives |
Number of employees | 35 (units built) |
The SNCF Class BB 900 consisted of 35 electric locomotives designed for mixed-traffic duties, constructed between 1936 and 1937 for the État railway company. This series was developed as a successor to the pre-war Midi Class E4700 and bore a strong resemblance to the subsequent Class BB 300 and Class BB 325 locomotives. Initially assigned to operate on the Paris–Le Mans route, these units remained in service for five decades until their retirement in 1987.
Background
During the early 1930s, against the backdrop of an economic downturn and the implementation of the Marquet plan aimed at boosting employment through large-scale infrastructure projects, the French government resolved to electrify the railway line connecting Paris-Montparnasse and Brest, passing through Le Mans. To support this initiative, the État company commissioned two distinct locomotive series: the Class 2D2 5400 specifically for passenger transport and the BB 900 series intended primarily for freight operations.
The BB 900 locomotives were derived from the successful Midi E 4200 and E 4700 classes. They were adapted with modified gear ratios tailored for the relatively flat terrain of the Paris-Le Mans corridor and were designed without rheostatic braking systems, which were deemed unnecessary given the route's gentle gradients.
Operational Use
Ordered by État from Alsthom in 1934 and originally numbered BB 101 through BB 135, this class was delivered over 1936–1937 and allocated to the Montrouge depot. Their main function involved hauling substantial freight loads on the newly electrified Paris-Le Mans line, although they occasionally handled passenger services using Talbot trainsets. Performance tests demonstrated that a BB 900 could rival a Somua Z 3800 railcar, reaching speeds up to .
One locomotive, numbered BB 125, was lost in July 1944 when it was destroyed during a USAAF air raid targeting the Maintenon viaduct.
Following SNCF’s renumbering scheme in 1950, these units were redesignated as BB 901 through BB 935, with BB 925 excluded. The class underwent significant refurbishments in the 1960s; several locomotives were transferred to Limoges depot shortly thereafter, with more following by mid-1970s. The gradual phase-out of this series occurred between 1982 and 1987 as SNCF modernized its electric locomotive fleet.
Technical Specifications
The BB 900 class incorporated advancements based on Midi designs, delivering greater power compared to the earlier BB 4700 models. Its welded steel body was structurally integrated with the frame and included two driver cabs. The bogies were connected via shock absorbers to enhance stability.
Each traction motor was nose suspended—supported on one end by helical springs attached to a bogie cross member and on the other by the driven axle—with power transmitted bilaterally at a gear ratio of 3.273.
Electrically, four M1E motors rated at each (1500 V) could be arranged in series, series-parallel, or parallel configurations. Unlike previous models, these locomotives did not feature rheostatic braking due to operational considerations on their assigned routes.
Motor control was managed through a controller offering 29 notches with settings for series and parallel motor connections as well as resistor configurations. Operators controlled field weakening via a six-position shunt lever and selected direction using a dedicated switch. Power collection utilized two Faiveley pantographs; high-voltage systems included double disconnect switches alongside circuit breakers. Motor circuits were engaged through electro-pneumatic contactors.
During mid-life overhauls, modifications included removal of end doors and comprehensive updates to engine controls and wiring systems.
Fleet list
| État number | SNCF number | Entry into service | Retirement date |
|---|---|---|---|
| BB 101 | BB 901 | 1 January 1936 | 27 April 1984 |
| BB 102 | BB 902 | 1 October 1936 | 26 June 1984 |
| BB 103 | BB 903 | 1 January 1937 | 22 January 1985 |
| BB 104 | BB 904 | 1 January 1936 | January 1982 |
| BB 105 | BB 905 | 9 December 1937 | December 1983 |
| BB 106 | BB 906 | 1 October 1936 | December 1983 |
| BB 107 | BB 907 | 3 October 1936 | January 1982 |
| BB 108 | BB 908 | 10 October 1936 | 28 February 1987 |
| BB 109 | BB 909 | 1 January 1936 | 28 February 1987 |
| BB 110 | BB 910 | 26 October 1936 | January 1982 |
| BB 111 | BB 911 | 1 January 1936 | 7 January 1985 |
| BB 112 | BB 912 | 21 July 1937 | 12 September 1984 |
| BB 113 | BB 913 | 13 July 1937 | January 1982 |
| BB 114 | BB 914 | 27 April 1936 | 31 May 1985 |
| BB 115 | BB 915 | 6 July 1937 | 5 March 1987 |
| BB 116 | BB 916 | 6 July 1937 | 30 August 1985 |
| BB 117 | BB 917 | 3 July 1937 | January 1982 |
| BB 118 | BB 918 | 1 January 1937 | December 1983 |
| 'BB' '119' | 'BB' '919' | '1 January' '1937' | 'January' '1982' |
| 'BB' '120' | 'BB' '920' | '1 January' '1937' | '16 April' '1985' |
| 'BB' '121' | 'BB' '921' | '1 January' '1937' | 'December' '1983' |
| 'BB' '122' | 'BB' '922' | '1 January' '1937' | 'December' '1983' |
| 'BB' '123' | 'BB' '923' | '1 January' '1937' | '30 May' '1984' |
| 'BB' '124' | 'BB' '924' | '1 January' '1937' | '3 April' '1987' |
| 'BB' '125' | '1 January' '1937' | '25 July' '1944' | |
| 'BB' '126' | 'BB' '926' | '1 January' '1937' | '28 February' '1987' |
| 'BB' '127' | 'BB' '927' | '1 June' '1937' | '19 March' '1984' |
| 'BB' '128' | 'BB' '928' | '10 August' '1937' | '28 February' '1987' |
| 'BB' '129' | 'BB' '929' | '1 January' '1937' | '28 February' '1987' |
| 'BB' '130' | 'BB' '930' | '5 August' '1937' | '19 March' '1984' |
| 'BB' '131' | 'BB' '931' | '1 January' '1937' | 'January' '1982' |
| 'BB' '132' | 'BB' '932' | '1 January' '1937' | '14 June' '1985' |
| 'BB' '133' | 'BB' '933' | '4 August' '1937' | 'December' '1983' |
| 'BB' '134' | 'BB' '934' | '29 July' '1937' | 'December' '1983' |
| 'BB' '135' | 'BB' '935' | '13 October' '1937' | 'January' '1982' |