Why did the transcontinental railroad industry devise time zones?

Answer 1

Prior to construction of the railroad, local time was roughly calculated by the sun's position at noon and towns therefore kept different time. It might only have been a matter of minutes and didn't really matter much with travel by foot, horse, wagon, or coach. But when the railroad was completed, it made scheduling a nightmare and actually posed a serious hazard which resulted in fatal collisions between trains which were operating on the same schedule but were effectively using differing local times. So time had to be standardized to accommodate the railroads and mitigate the hazard of collision. Part of this standardization was the development of time zones, where ever 15 degrees of longitude equals one hour difference.

So the trains could run on time and to avoid collisions with other trains.

Because that was the way people got around, so there had to be a way to know the schedule for the trains in more than one place.

As even shorter distances were traveled before the transcontinental railroad was fully completed, there were 50 US time zones. This was all corrected to have time zones "make sense'.

Answer 2

North American railroads did not adopt time zones until 1883, when the system devised by William F. Allen was adopted. These time zones were not based on any principle, but were drawn to have changes of time zone occur in major cities. The Canadian railway engineer, Sir Stanford Fleming, promoted a system where time zones worldwide would be in roughly 15 degree increments from the meridian running through Greenwich, England, and this was eventually adopted to replace Allen's system.