Line 4 () is one of the sixteen currently opened lines of the Paris Métro, as well as one of its three fully automated lines. It connects Porte de Clignancourt in the north of Paris, to Bagneux-Lucie Aubrac in the eponymous southern suburban city, on a north-south axis across the French Capital. Held within the boundaries of the City of Paris for over a century – until its southern terminus was changed from Porte d'Orléans to Mairie de Montrouge in 2013 – the line was sometimes referred to as the Clignancourt – Orléans Line. At in length, it connects with all Paris Métro lines apart from the very short 3bis and 7bis branch lines, as well as with all 5 RER train lines. It also serves three of the Paris Railway stations, Gare du Nord, Gare de l'Est, and Gare Montparnasse.
Line 4 was the first line to connect to the south side of the River Seine, through an underwater tunnel built between 1905 and 1907. Line 4 long ran the longest-serving MP 59 rubber trains, which used rheostats to dissipate the braking power through resistance, making line 4 the hottest line in the system. Those trains were withdrawn from service on Line 4 during the course of 2011 and 2012 after 45 years (with some being in service for 50 years), yet remained another 12 years on in service on Line 11. On Line 4, they were replaced by the MP 89 CC stock transferred from Line 1, right after its automation.
In 2013, Line 4 was extended for the first time since its initial construction, into the southern suburbs of Montrouge. The line was further extended to Bagneux–Lucie Aubrac in 2022, connecting to the future Grand Paris Express. The line has been retrofitted for full automation, with the first automated trains commencing service on 12 September 2022.
History Chronology 21 April 1908: A first section of the line was inaugurated to the north of the Seine between Porte de Clignancourt and Châtelet. 30 October 1909: A second section of the line was inaugurated south of the Seine between Porte d'Orléans and Raspail. 9 January 1910: Both sections were linked by a new tunnel between Châtelet and Raspail. Line 4 was the first line crossing the Seine river underground. 1967: The rails were converted in order to cater for rubber-tired trains. The MP 59 rolling stock replaced the steel-wheeled Sprague-Thomson stock. 3 October 1977: The station Les Halles was rebuilt to interchange with the new RER network. 23 May 2011: Cascading of MP 59 to MP 89CC rolling stock began. 21 December 2012: The last MP 59 (#6021) was withdrawn after 45 years of service on Line 4. 23 March 2013: Extension south to Mairie de Montrouge officially opened to passengers, marking the first extension of Line 4 since its inception. 2016: Automation work begins. 13 January 2022: Extension south to Bagneux-Lucie Aubrac officially opened to passengers. 12 September 2022: First automatic trains (MP89, MP05 and MP14) enter service 15 December 2023: Last day of driver operated services
Origins
Line 4, opened in 1908, was the last line of the original concession of the Compagnie du chemin de fer métropolitain de Paris and the first to cross the Seine underground (Line 5—now Line 6 at this point—crossed the river on the Passy bridge, later renamed the Pont de Bir-Hakeim in 1906). The route was the subject of lengthy discussions that delayed the start of construction of the tunnel. It was originally planned as a straight line under the Rue du Louvre, under the Seine in line with the street, under the Institut de France, along the Rue de Rennes and then the Boulevard Raspail to the Porte d'Orleans.
But as a result of the delay in the extension of the Rue de Rennes as part of Haussmann's plan towards the Seine—which was never carried out—and the outcry from the academicians who refused categorically the line passing under the Institut de France, the route was eventually changed to cross further east through the Place du Châtelet and the Île de la Cité. The new route also has more coherence as a north–south route following the main traffic flows. A second modification of the route was also made: it was decided to make a temporary deviation via the major station of Gare Montparnasse to avoid a further delay in opening the line, which was eagerly awaited. This was made necessary by the delay in building the new Boulevard Raspail between Rue de Rennes and Boulevard du Montparnasse. Once the Boulevard Raspail was completed, it was planned to take the shorter route and bypass the Gare Montparnasse. To the south of the Vavin station the tunnel provides for the final route along the Boulevard Raspail. But the value in serving three major mainline stations by the line later led to the abandonment of this proposal.
A spectacular construction site In 1905 construction was started by the company of Léon Chagnaud—a former mason from Creuse (a department with a tradition of supplying building workers in France)—and line 4 became the first to cross the Seine underground. The method used for crossing under the river is that of metal caissons, twenty to forty meters in length mounted on the banks and sunken vertically in the river bed. The ends of the caissons were blocked and they were towed to their location before being ballasted with water and sunk in the riverbed. A chamber filled with pressurised air was built at the lower level of these caissons so that workers could excavate under the caissons. Each caisson gradually sank to its final position as the ground below it was removed. The northern stream of the Seine required three caissons, the southern stream two caissons.
The crossing of the Seine also involved the freezing of saturated ground between the station of Saint-Michel and the Seine, under the line of the Chemin de Fer de Paris à Orléans (now RER line C) in 1908 and 1909. The installation of two refrigeration plants allowed the movement of brine cooled to −25 °C in dozens of tubes to stabilize the ground.
The northern section was the first completed: it was opened on 21 April 1908 from Porte de Clignancourt to Châtelet. The southern section was opened 30 in October 1909 from Porte d'Orleans to Raspail. The two sections were connected on 9 January 1910. However, the line was closed to traffic a few days later in January 1910, when the level of the Seine broke its banks during the worst flood of the century. On the morning of 24 January 1910, a significant inflow of water at the Seine crossing interrupted services between Châtelet and Vavin, although services were restored later in the day. But the inflow increased and services were again halted in the afternoon. On 26 January Châtelet station and the crossing under the river was completely flooded and slowly rose in the tunnel. On the night of 27 and 28 January, flooding reached Réaumur – Sébastopol and eventually Gare de l'Est: The line at its minimum was reduced to operating between Clignancourt and Gare du Nord and between Vavin and Porte d'Orleans. The fall in the level of flooding during February allowed a gradual resumption of operations, but full service was not restored to 6 April after repair of extensive damage caused to the infrastructure.
During the politically turbulent 1930s, Line 4 had its own drama: on 27 July 1934, a package left in a carriage was carried into the office of its chief supervisor, located on the platform of Montparnasse. The package exploded, killing the chief supervisor and another officer and wounding four passengers. The assassins were never found.
During World War II the most violent bombing Paris suffered was on the night of 20 and 21 April 1944 when the rail freight yard of la Chapelle and the main truck workshop at Rue Championnet were hit. The roof of the Simplon station was hit by a bomb and it collapsed on the tracks and platforms. After repairs the line was brought back into service a few days later.
The rubber tyre metro and the deviation of the line
The RATP was satisfied by experimentation with rubber tyres on Line 11 beginning in 1956. It therefore decided to equip lines 1 and 4 for rubber-tyre operations, which can increase line capacity by providing better acceleration and decelerations as a result of a much superior grip.
In the early 1960s these two lines were the two busiest on the network, with loads of 140% of capacity during the evening peak. However, as this change alone was insufficient to overcome this saturation, the length of stations was lengthened from , allowing the lengthening of train from five to six carriages. This work was carried out very quickly and, as early as October 1965, trains of six carriages traversed the line. On 3 October 1966, the first train composed of MP 59 electric multiple units operated on the line. The Line 4 trains were identical to those on Line 1, being composed of four motors and two trailers per train. The line's MP 59 fleet included 556 carriages: 376 powered carriages and 180 trailers. On 17 July 1967, the last steel-wheeled train left the line to strengthen the service of others with a hundred cars built before 1914 scrapped. In February 1971, line 4 was the second network after line 11 to be equipped with semi-automatic operation, with a system known as Grecque ("Greek"). This allowed trains to run automatically once started by the driver and stop at the next station.
Since its opening the only change of the route of the line took place in early October 1977 with the deviation of the line with the relocation of the station at Les Halles. During the excavation of the enormous Les Halles complex the station of Les Halles was relocated about ten metres further east to allow a shorter connection to Châtelet – Les Halles RER station. For this, three hundred and thirty meters of tunnel were built to join the old route. The changeover took place on three consecutive nights from 10 PM on Friday, 30 September 1977 to the beginning of services on Monday, 3 October. On the first night, the new track 2 was connected, on the second night, the new track 1 was built and on the last night it was connected.
On 6 August 2005 at 4:42 pm, a fire on a train at Simplon due to the malfunction of a circuit breaker caused the evacuation of two MP 59 trains with 19 people mildly affected. The fire was extinguished by fire fighters at around 6:00 pm.
Extension to Montrouge and the MP 89
Until 2013, Line 4 was one of a few lines (the others being semicircular lines 2 and 6, as well as the then new Line 14) that had never been extended beyond the "gates" of Paris. During the 1920s, a preliminary extension towards la Vache-Noire was planned but never carried out. Since that time, no other extension plan was brought up. In 2008, nearly a century after its opening, construction of a one-station extension towards began. The new station officially opened to passengers on 23 March 2013, allowing one to travel from Montrouge to Clignancourt in 30 minutes.http://www.ratp.fr/fr/ratp/c_5097/actualites/ La ligne 4 arrive à Montrouge - RATP - Retrieved 3/23/2013 (In French) Mairie de Montrouge is a traditional two-tracked station.
In addition to the Montrouge extension, in 2011 there has been a much needed refreshing in rolling stock for Line 4, as the MP 59 trainsets were reaching the end of their useful lives. The automation of Line 1 and purchasing of new automated rolling stock (the MP 05) allowed the RATP to replace the MP 59 with the MP 89CC rolling stock from Line 1. Testing of the MP 89 during overnight hours took place in 2010, with the first train (#01) to be transferred to Line 4 in April, 2011 and enter service on 23 May 2011. A second train (#44) entered service on 10 September 2011. The first MP 59 train that was retired was #6049, which was pulled from service in April, 2011.