But the clocks were still aligned with the local noonday sun. Following the invention of the locomotive in 1830, time had to be synchronized across vast distances in order to organize the train schedules. This eventually led to the development of time zones, and, thus, global isochronous time. These time changes were not accepted everywhere right away, because many people's lives were still tied closely to the length of the daytime. With the invention in 1879 of the light bulb, that changed too.