Abstract: A protective collar for tank cars, which are used for the transport of materials capable of causing corrosion on the exterior surface of the tank car, is formed approximately in the shape of a downwardly facing C and is placed over the exterior upper surface of the car in the area of the car manway and associated fixtures, normally midway between the car ends. The collar is made of stainless steel or other such protective materials and is provided with apertures to accommodate the tank car manway and associated fixtures. The collar preferably is secured to the exterior surface of the car by means of a frame welded to the car surface and slidingly engaging the periphery of the collar to accommodate differential expansion between the collar and car.