There are many different types of metal railings to choose from. Since metal can be transformed into so many different shapes and sizes the options are limitless.
Landscape architects can use all types of metal railings to accent any landscape.
Most railings such as these above were pre-manufactured at a factory then installed on site with little or no welding required. This is the one major consideration that needs to be made when putting a metal railing in a landscape. It takes skilled labor to custom build railings on site plus it is nearly impossible to bring shop equipment that is needed to the job site. The railing that is used in the picture on the right is most likely made of carbon steel, the most widely used steel for this type of railings. Since there is very little signs of rust the railing was either dipped in paint or a baked on paint finish was implied at the factory where it was manufactured.