When the trains set the clocks

Until the middle of the nineteenth century, nobody much minded that every town kept its own time. Noon was the moment the sun stood highest over the local church, and since the sun reaches its peak a little later the further west you go, clocks in Bristol ran about ten minutes behind those in London. For people who travelled on foot or by horse, the difference was irrelevant: by the time you had ridden from one city to the other, a few minutes here or there hardly mattered. The railway changed all that and, in doing so, changed something more fundamental than timetables.

A train that leaves London at noon and arrives in Bristol some hours later raises an awkward question: whose noon? With every station keeping local time, timetables became a nightmare to compile and to read, and the risk of collisions on single-track lines was all too real. In 1840 the Great Western Railway took the obvious step of running its entire network on London time, and within a decade almost every railway in Britain had followed suit. Towns were left with a choice between two clocks, and for a while some chose both: the clock on Bristol's Corn Exchange still has two minute hands, one for local time and one for the railway.

It would be tempting to see the outcome as inevitable, but the change met with considerable resistance. Critics complained that a private company had no right to tell a town when its day began, and some local authorities clung to sun time for years. There was something almost religious about the objection. Time, after all, had always seemed a natural fact, written in the sky; now it was being set by an office in London for the convenience of shareholders. Not until 1880 did Parliament make Greenwich Mean Time the legal standard throughout Great Britain, by which point the law was largely catching up with practice.

In North America the problem was even more acute. By the early 1880s the railways of the United States were using dozens of different local times, and a passenger crossing the country might have to reset their watch over and over again. On 18 November 1883, the railway companies took matters into their own hands and divided the continent into four time zones. In many cities clocks were stopped or turned back at midday, giving rise to what newspapers called 'the day of two noons'. Remarkably, the federal government did not give these zones the force of law until 1918; for thirty-five years, the nation's official time was essentially a private arrangement between companies.

The following year, delegates from twenty-six countries met in Washington and agreed to measure longitude from Greenwich, laying the foundations of the time zones we take for granted today. Yet the deeper legacy of railway time is psychological rather than administrative. Once clocks were synchronised across a whole country, punctuality became possible on a national scale and, before long, expected. The factory shift, the school bell and the nine o'clock meeting all depend on the quiet assumption that everyone's watch says the same thing. Lateness, once a matter of a few minutes against the church bell, became a failing measured against the whole nation.

It is worth remembering this the next time your phone silently adjusts itself after landing in a new time zone. The time it displays is not a fact of nature but a convention, negotiated by engineers, businessmen and politicians and imposed, at first, against the wishes of many of the people it governed. Nor is the argument over: several countries have moved their clocks for political reasons in living memory, and until 1975 Saigon kept its clocks an hour ahead of Hanoi's. That we now experience it as natural is perhaps the clearest sign of how completely it won.