This week’s freight car – tank cars! At first glance, you’d think just about every tank car looks the same. There are actually many variations in tank cars – appropriate for the variety of loads they carry.
The first tank cars appeared in the late 1880s and 1890s. They were basically wooden vats placed on flatcars.
The first major revision to this design came with the substitution of a horizontal steel tank for the vats. A dome at the top of the tank provided a place to load the liquids, and also room for expansion of the load in transit. Flatcars gave way to smaller frames, and by the 1960s, the tanks themselves became the integral part of the structure.
Tank cars can be used to carry a plethora of products. Among the most common are oil and petroleum products, foodstuffs like corn syrup, and chemicals. Some of these fall into the hazardous materials category.
The tanks themselves are often customized for these loads. Some are hard to spot, like insulation and even heating coils used to help unload products like asphalt. These are placed inside an outer wall around the tank.
More visible are multiple-compartment tank cars, easily spotted by their multiple domes. Once used for shipping smaller quantities or even multiple products, these cars are far less common today as trucks have captured a large part of those markets. Fittings used for loading and unloading also vary greatly, providing interesting modeling opportunities for those who like to add extra details.
Paint is another common variation. Basic black is most common today. White is sometimes used for loads that need to be kept cooler in transit. It used to be quite common for shippers to paint their cars with bright colors and large logos. This practice largely disappeared in the 1980s but is making a come-back on many of today’s ethanol and corn syrup tanks.
The vast majority of tank cars are owned by private leasing companies, not by the railroads. This is more efficient for the billing end of railroad operations. Railroad companies often own a few cars for their own use, such as transporting fuel to remote stations or for work trains.
Large or small, black or orange, tank cars represent an interesting and essential part of the freight car fleet.