A rail means a bar, so the railing is a set of bars. Usually they are used to enclose an area. It is believed that first gardens were closed by railings and this led us to fences.
At first timber was used as a material because it was cheap. There are also notes that cast iron and wrought iron (also known as worked iron) were used but only for wealthy houses because these materials cost more then than they do today.
Wrought iron means ‚worked iron' which means that it is heated in a funance until it is red and then it is hammered on an anvil to a desired shape. Cast iron on the other hand means that the metal is heated until it is liquid and then it is poured into moulds eith appropriate shapes.
This was a way of showing off to one's neighbours in the old times. When choosing an iron railing, it is important to use means to prevent it from rusting.
When choosing vinyl for the material of the railing, you will get beautiful appearance without maintenance and high lifetime cost of wood or metal. This type of material works best for creating traditional and elegant look to the area that you have encircled with a railing.