Before proceeding to discover the meaning of the term iron, we will know its etymological origin. In this case, we can establish that it comes from Latin, exactly from the word "ferreus", which is the result of the sum of two lexical components of that language:
-The noun "ferrum", which means "iron".
-The suffix "-ea", which comes to indicate "relationship".
The first meaning of the term mentioned in the dictionary of Royal Spanish Academy (RAE ) refers to what is of iron or that has the characteristics of this material.
In this sense, it is known as Railway Line or railroad track to the road built from iron rails which are arranged in parallel, on which the trains . The railway, therefore, constitutes a key infrastructure for rail transport.
The development of a railroad requires several jobs . On the one hand, the floor must be prepared for the correct installation of the rails. On the other hand, drains, bridges and other necessary elements must be manufactured so that trains can proceed safely.
In general, the rails are separated according to the separation of the wheels of the trains. At that distance, which constitutes the width of the railway, it is known as gauge .
It is interesting to know that not all over the world there are the same railroad widths. Thus, for example, while in the United States it is 1,676 millimeters, in Spain and Portugal it is 1,668 millimeters and in Japan it is only 1,000 millimeters.
This measure has a long history behind it, which began in the 19th century when the mines were running and had a track width of between 1.40 and 1.50 meters. And that was the one that was used when the railway steam machines were launched. However, shortly thereafter it was decided to change that width so that the curves were taken much better.
In addition to all of the above, we cannot ignore that other reasons to modify that measure are the orography of the place where the train in question circulates and what are reasons at the economic level. But it is not all, because it is also considered that there are military criteria, specifically defense. Yes, because it is believed that since there are different railroad widths it is more difficult for a country to attack another that has that measure different from its own through trains where weapons are transported, for example.
By analogy to the properties of iron, the idea of iron is used to qualify something that stands out for its tenacity , his rigidity or his hardness . For example: "Despite their efforts, the local team failed to overcome the strong defense of the visiting team and the match ended evenly", “Every project presented by the government meets the strong opposition of the rest of the political parties”, "The controversial statements of the actor provoked a strong reaction from associations that defend the rights of animals".