The 'Micheline' - the first train on pneumatic tyres. In commercial use since 1931 - the birth of the Michelin Tyre. This example was run on the L.M.S. Line (Bletchley to Oxford) in 1932. Michelines offered unprecedented ride smoothness, but they soon proved to be problematic because the low load that the wheels could bear limited railcar sizes and demanded a high number of tyres (up to 20) per car. Furthermore, they were subject to flat tyres, unlike cars with steel wheels. The trains of the Paris metro (RATP) still run with rubber tyres.