During the Showa era, when rail transportation played a leading role in logistics, railroad luggage transportation was carried out by luggage cars connected to passenger trains, but dedicated luggage trains were operated as the transportation volume increased. As a result, express luggage trains were also operated on main lines such as the Tokaido / Sanyo Main Line and Tohoku Main Line.
A considerable number of luggage passenger cars modified from old passenger cars were arranged, and a variety of luggage trains composed of steel postal cars, pallet luggage passenger cars and postal passenger cars were seen.
In 1968, pallet transportation began with a new pallet car that appeared as a trump card for the modernization of cargo transportation.
At first glance, it looks like a freight car, but it has been incorporated into luggage trains and express trains and has been active nationwide.

The Suyu 44 is a pallet cargo handling postal car that appeared in 1971, and is a privately owned passenger car owned by the Ministry of Posts and Telecommunications. Only the roof and wife's surface are blue, and 24 pallets can be stored in the aluminum press structure. Due to the abolition of railroad postal transportation in 1986, all cars were scrapped the following year.