4 access bridges with safety cages for accessing the tops of tank cars from a platform. These bridges are half-way up, to allow trains to pass underneath but also appear to be in the loading process when a tank car is spotted below the bridge. These are specifically designed for use on to of my N Scale Tank Car loading Platform type 1 and type 2. They can be mounted on other structures as well, as long as the walkway is 30mm above the track.