Unit trains come in all shapes and sizes. Unit train shipments of oil, gasoline and chemical products are nothing new. But when General American Tank Car (GATX) introduced the “Tank Train” the 1970s, there was an added twist.
The Tank Train features tank cars that are semi-permanently coupled in blocks of 12-15 cars. In addition to the standard railroad couplers, a 10 inch interior-diameter flexible hose bridged the gap between cars. With this, the entire string could be loaded or unloaded from a single connection. Not only did this greatly speed loading and unloading, it reduced the chance for spillage and the hoses acted like a cushioning device taking the slack out of the train while in motion. The cars were developed in GATX’s Sharon, Pennsylvania facility by Chief Engineer, Erling Mowatt-Larssen. The train sets helped win service away from GATX’s top competitor Union Tank Car (UTLX).
The last car in the string is only filled 3/4 with product, then pressurized with nitrogen. This helps purge the tanks of any remaining product as they are unloaded. Thanks to the connections, cars can be loaded / unloaded at a rate of 3,000 gallons per minute. A cut of 5 cars can be filled / emptied in 9 hours with just two people. An entire 90-car train could be turned as quickly as 5 hours.
Although the cars are most commonly associated with the Southern Pacific and their services which took the “oil cans” over the famous Tehachapi loop in the 1980s, the Tank Train has been used on the Alaska Railroad, Canadian National, Vermont Railway, Delaware and Hudson, Grand Trunk, Conrail and others. After a few breaks in service, GATX still lists the Tank Train on their website.
The cars have come in a variety of capacities for different products including: crude oil, fuel oil, gasoline, LPG, phosphoric acid and other chemicals. Car capacities range from 14,500 to 33,500 gallons.
While the trains provided many advantages to the shipper, they did create a few extra headaches for the railroads. If a car developed a mechanical problem, the entire cut would have to be set out. Also, the train had to be kept properly oriented, and sometimes turning blocks or entire trains on a wye or reverse loop was necessary so they could be spotted for unloading.
Although not in the current catalog, these distinctive tank cars have been offered in several paint schemes by Lionel in the recent past. Of course they would look great behind a pair of Southern Pacific Tunnel Motors, but they’d also be right at home behind lots of other power. You could model a refinery or distribution center, or the actual unloading point could be “just around the corner” as you spot a cut of these cars on a long siding. Don’t forget to make sure the train is properly turned! Whether you’re switching the cars or just watching the oil cans roll – the Tank Train is sure to be a hit on any model railroad.