Right and Left
Line 4 was the first line to connect the Right and Left Banks of Paris via an underwater tunnel, built between 1905 and 1907. Line 4 long ran the oldest cars in service on the system, the MP 59, which used rubber tyres to dissipate the braking power through resistance. Those trains were withdrawn from service during the course of 2011 and 2012 after 45 years (with some being in service for 50 years). They were replaced by the MP 89 CC stock from Line 1 when the latter line was automatised. "(From )".