Answer :
Before international time-zones were created international travel was a nightmare because many countries used random time scales. Time-zones made everything uniform and thus more reliable.
Before the creation of time zones, every village and town would have had its own time. This made travelling very difficult, as you would have had to know not only what your local time was, but the way in which all other towns measured time. The development of time zones allowed different towns within the same region to have exactly the same time. This meant that train schedules could be designed using only this time, and without the need to compare among different localities.
