J line

Transport: the RER E will eventually replace this branch of Line J.

Starting February 28, 2027, the RER E will be extended to Mantes-la-Jolie in Yvelines. A welcome development for many commuters, but it will carry consequences for travelers on Transilien Line J. In the long term, the J5 branch linking Paris Saint-Lazare to Mantes-la-Jolie via Poissy will disappear and be replaced by the RER E. Here’s what you need to know.

Line J: No trains to Mantes-la-Jolie on 11–12 July 2026.

The Mantes-la-Jolie station in Yvelines is bracing for a troubled weekend around July 14: services on the J line and on the Normandy trains will be heavily disrupted, or even completely suspended, from July 11 to 14, 2026, with replacement buses in operation.

Line J: trains canceled and overnight suspensions until June 5 in Yvelines

Line J of the Transilien will run in degraded mode from June 1 to 5, 2026: trains canceled at Conflans-Sainte-Honorine and nightly suspensions from 9:40 p.m., a situation affecting around 90,000 passengers daily in Yvelines.

Line J has been interrupted for several days at Paris Saint-Lazare.

Major infrastructure work will disrupt the J line in February and March 2026. On Sunday, February 8, as well as the weekends of February 14-15 and March 7-8, there will be no train service between Paris Saint-Lazare and Argenteuil, Ermont-Eaubonne, and Houilles Carrières-sur-Seine.