This article is published in partnership with Quoraa platform on which Internet users can ask questions and where others, specialists in the subject, answer them.
The question of the day: “What was the first French electric speed locomotive?”
–
–
The answer of Philip Castle:
Before talking about electric speed locomotives, a brief history of electrification in France must be made. The pioneer network in terms of electrification was the network of the South Company, the only major company not to have a Parisian station. The network occupied the greater South-West and in particular covered the entire chain of the Pyrenees and the south of the Massif Central. A partly mountainous network, therefore. But also a network that does not have direct access to coal and that does have significant hydroelectric potential.
From the beginning of the XXe century, the Midi embarked on numerous experiments in electric traction and determined a very “Swiss” electrification program which resumed the use of alternating current (12 kV single-phase 16 2/3 Hz) as a priority on mountain lines. Even the E 3000 prototypes look very Swiss.
But above all, these prototypes have an axle arrangement that will be found in speed machines after the First World War: carrier axle, group of driving axles, carrier axle (1C1).
Initially limited speed
The post-war period also marked an important transition in electrification in France. The government imposes the standard of 1.5 kV direct on all standard gauge lines, by catenary or by third rail. Le Midi, still at the forefront in this area, is reviewing its entire electrification program, abandoning single-phase prototypes, and developing two techniques that will mark French electric traction.
1. The 1.5 kV catenary
The characteristic ogive system for alignments and large radius curves, and “pulled” catenary in curves.
A 1.5 kV catenary, here in Villeneuve-Saint-Georges, in Val-de-Marne. | JH Mora via Wikimedia Commons
2. The BB locomotive
For mountain lines, the Midi does not need speed, but rather grip. The company’s engineers will invent what will be the model of all-purpose locomotives until the 1970s: a locomotive of average power together bogies of two driven axles (BB), which can be coupled in multiple units, which makes it possible to have comfortable power distributed over eight or twelve axles.
These machines are limited to 100 km/h, the traction motors are “suspended by the nose”, that is to say that they pose on the axle at one end and mesh with a cog wheel integral with the axle on the other. This arrangement, which has the advantage of simplicity, has the major drawback of increasing the unsprung masses and therefore of limiting the speed. From 1922, two types of locomotives were delivered by Electrical Constructions of France (Tarbes): the E 4000 and the E 4500.
120 kilometers per hour
But back to speed machines. In 1920, the Midi took over one of its “big wheel” machines and suspended motors to operate it at 1.5 kV. This machine was released as a 1C1 prototype in 1914.
Due to the war, all prototypes are put on hold. In 1920, following the government’s electrification decision, the 3101 was completely redesigned, fitted with three DC motors operating at 500 V mounted in series, and the supporting axles were doubled due to weight gain; the machine becomes a 2C2. The motors are mounted vertically and transmission to each axle is through a pair of bevel gears. The lubrication of the whole is done by a circulation of pressurized oil, which does not prevent the pairs of gears from wearing out very quickly and having a problematic lubrication on the upper bearings.
Despite these drawbacks, in 1922, the Midi had the first real high-speed electric locomotive (120 km/h).
The electric locomotive E 3109. | Wikimedia Commons
At the same time, the PO (Paris-Orléans) began its electrification and, in 1926, the Paris-Vierzon section was inaugurated. The PO asks the CEM Fives-Lille establishments to study a locomotive capable of towing heavy express trains at 130 km/h. In 1926, the E 501 and E 502 prototypes were delivered. These are 2D2 (two tag axles, four driving axles, two tag axles).
To ensure a high-speed transmission without increasing the unsprung mass, the four motors are fixed in the body and it is once again in Switzerland that we will look for the solution. This will be the Buchli system, developed by the Brown-Boveri company.
“Pig’s nose”, “pregnant woman”…
For thirty years, the 2D2, brought to 140 km/h thanks to the replacement of the friction bearings by roller bearings, will be the queens of speed on the electrified lines of France. Three sub-series of this machine were delivered from 1926 to 1942. The first sub-series had received the nickname “pig’s nose”, it is the type 501/502, the E 501 to E 537 (2D2 5501 to 5537 SNCF). The second sub-series was nicknamed “pregnant woman”, E 538 to E 545 (then 2D2 5538 to 5545 SNCF).
2D2s 5546 to 5550 were delivered to SNCF in 1942 and were nicknamed “Waterman”.
The State network electrifies Paris-Le Mans in 1937 and orders a series very close to the E 500, the 2D2 501 to 523. The aesthetics of this series foreshadows that of the last representatives of the line.
The last 2D2s manufactured in France were the 2D2 9100 delivered in 1950-1951 for the electrification of the axis Paris-Lyon-Mediterranean.
–
The 1950s will see the beginning of the decline of these magnificent machines with the appearance of faster and more efficient series such as the CC 7100, BB 9000, BB 9200…
–
