A Pullman can is called “Pullman” because its long rectangle shape looks like a railway car.
It’s not a standard can size, though. The length can vary from 20 to 50 cm (8 inches to 20 inches.) The other dimensions can vary as well: 10 x 10 cm (4 inches tall x 4 inches wide), or 10 x 25 cm tall (4 inches wide x 10 inches.) The US Army and US Air Force specify that they want their canned ham in 10 x 15 cm (4 x 6 inch) Pullman cans.
Depending on their size, the cans can hold 1 3/4 to 7 1/4 kg (4 to 16 pounds) of meat.
Pullman cans are usually used for meat products such as ham, corned beef, and other luncheon meat such as spam.