(Demiryolu) A guard rail (check rail) is a short piece of rail placed alongside the main (stock) rail opposite the frog. These exist to ensure that the wheels follow the appropriate flangeway through the frog and that the train does not derail
A guardrail is a railing that is placed along the edge of something such as a staircase, path, or boat, so that people can hold onto it or so that they do not fall over the edge