In 1826 and 1827, two Prussian engineers visited Britain to look at a number of railways, and the construction and operation of the Hay inclined plane was described in some detail in their subsequent publication. The rails were made of cast iron, and were "L" shaped in section. The running surface was wide by thick, while the vertical flange was tall and thick. They were described as the strongest and thickest that they had seen. Most of the incline was laid with only three rails, with a small section in the middle which had four rails, so that the boats could pass one another. Because the flanges were on the rails rather than on the wheels as in modern railway practice, one track had the flanges on the inside, and the other on the outside. The rails were fixed to timbers running along the incline, square, which were attached to wooden sleepers which ran across the incline.