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 8 inches to 20 inches (20 to 50 cm.) The other dimensions can vary as well: 4 inches tall by 4 inches wide (10 by 10 cm), or 4 inches wide by 10 inches tall (10 by 25 cm.) The US Army and US Air Force specify that they want their canned ham in 4 by 6 inch (10 to 15 cm) Pullman Cans.
They can hold depending on their size 4 to 16 pounds (1 3/4 to 7 1/4 kg) of meat.
Pullman cans are usually used for meat products such as ham, corned beef, and other luncheon meat.