for a buffet held in the rotunda. The press reports were laudatory, commenting on the smoothness of journey, and their brightness of the stations. From the beginning, the traffic on the line was significant and the quantity of rolling stock had quickly to be increased. From 5 November 1910 until 30 June 1911, the line carried 29,263,610 passengers. Developments to the present On 8 April 1911, the line was extended north to Pigalle. A subsequent three station extension to Jules Joffrin proved particularly difficult. The route passed underneath the hill of Montmartre, which had long been quarried and mined for gypsum to make plaster of paris. During the construction of the tunnel, numerous unknown quarries were discovered forcing a change in the line's route to avoid them. The two intermediate stations, Abbesses and Lamarck – Caulaincourt, are particularly deep: here the tunnels are situated and below ground level, respectively. The engineers constructed arches underground to support the weight of the gypsum above. The extension was put into service on 30 October 1912. Work on the final extension northwards began in September 1912, but the tunnel was not finished at the beginning of the First World War. Though lacking personnel, the construction work continued at a slower pace. On 23 August 1916, in the middle of the war, the line reached Porte de la Chapelle. This extension comprised three new stations, of which the final included three tracks and two central platforms, the central track being used by trains leaving or arriving. Line A intersected with Line 4 at Marcadet – Poissonniers, but no transfer had yet been set up. On 1 January 1930, the CMP absorbed the Nord-Sud company, and line A became line 12 of the Métropolitain network on 27 March 1931. The line that bore the number 12 in the 1922 plan for a complementary network, from Porte d'Orleans to Porte d'Italie, was abandoned. Thinking that the number of trains on the line was insufficient, the CMP transferred four trains from their holding to augment the service. The Nord-Sud company lines were powered through overhead cables, whereas the third rail system was in use on the CMP's network. With the ownership transition, the CMP standard was adopted on the lines 12 and 13. As a result, the overhead cables of the Nord-Sud were decommissioned in 1932, one year after those of line 13. Pantographs continued to be used