By 1845, Paris and the railway companies were already thinking about an urban railway system to link inner districts of the city. The railway companies and the French government wanted to extend main-line railways into a new underground network, whereas the Parisians favoured a new and independent network and feared national takeover of any system it built. The disagreement lasted from 1856 to 1890. Meanwhile, the population became denser and traffic congestion grew massively. The deadlock put pressure on the authorities and gave the city the chance to enforce its vision.