Prior to industrialization, the only ways to transfer people between places were walking or riding an animal. With the arrival of the steam engines appeared modern locomotive means, and doing things like a train ticket to Aix en Provence became easy and accessible to everybody. Furthermore, if we desire to land transport to important capitals and recognized landmarks, it is still the best option today.
Whether you take a relic of times gone by, with its charcoal engine and its characteristic rattle, or use the most advanced electrical or magnetic technology one, efficient and fast, all of them are able to easily displace large quantities of people and cargo. Usually you can shift with regular schedules and lacking of dealing with the typical annoyances and uncertainties of traffic jams.
Paying attention to history, it can be noted that those societies that had this method of mobilization were the greatest of their period. They were capable to colonize new lands as well as constantly maintain settlements at non-fertile places or away from water sources, simply because the ease of transferring quickly big amounts of supplies and labor. Not to mention its versatility in time of war.
In addition, its antiquity ensures that the rail system is as complete as possible, connecting cities and towns in intricate networks across continents; with some honorable mentions e.g. Eurotunnel that joins the United Kingdom with France, in a passage through and under the sea.
Of course, it cannot be denied that building the rails is a notable effort and investment, but the initial cost was straightforwardly surpassed by the profits obtained, even taking into account maintenance costs. So if you want to go to Tarragona and enjoy the scenery on the way, without worrying about driving your personal vehicle, prepare your bags and buy tickets at the nearest station, the experience is well worth it.