Unless they are the ones used on the railways, where the red light is on the bottom. Reason for this apparently, means that a build up of snow can't obscure it,

Unless they are the ones used on the railways, where the red light is on the bottom. Reason for this apparently, means that a build up of snow can't obscure it, causing a driver to not see it and ram up the back of another train. Of course nowadays, there's overrides to stop trains running red lights, but the red lights are still orientated at the bottom.