I have mentioned this before here; British sailing ships frequently brought railroad rail to the USA in the later 19th century. First it was iron and later steel. There is a four-foot square hatch in the ship Balclutha preserved here in San Francisco called the rail hatch. However, as far as we know, the ship never carried "railroad iron" as our British railway cousins called the rails. The cargo paid a little better than coal which was another common cargo coming to the West Coast.
In the 1890s, shortly before the Southern Pacific Railroad switched to oil, there was a cargo of steam coal delivered in the Balclutha from Newcastle, NSW to San Francisco. Remember that good quality coal had to be imported into the west in the late 19th century.
I am quite sure that both some of the 19th century iron and coal cargoes ended up on narrow gauge lines.
Ted Miles, retired but still interested