It was not until 1838 that a first lock was built to make sailing possible on the other branch of the Seine, which until then had been unusable. The river very rapidly became the major communication route between Paris and the English Channel. Barge and steamboat traffic, and regular passenger services, became so heavy that two new locks were built in 1883.

The population, with over 1000 inhabitants, was still largely composed of farmers, winegrowers and nurserymen who went to Paris to sell their goods. However the 19th century saw the advent of the industrial era and exploitation of the subsoil, which had begun in the 17th century, carried on with building stone and chalk quarries, “white mineral” factories, lime kilns, tileries and brickyards. Laundries and cotton carding mills introduced women into the world of work.

In 1837, the first railway line between Paris and Le Pecq was built with a stop at Rueil-Malmaison. Horse drawn carriages, followed by the horse drawn omnibus on rails (1854) and the steam train (1874) brought Parisians to the banks of the Seine and the countryside. In 1870, Bougival did not escape the war and many inhabitants fled from their village. Among those who remained, the gardener François Debergue became famous for cutting the telegraph lines connecting the Prussian garrison in the area to the headquarters in Versailles three times. He was shot on 6 September 1870.