Tomy's Super Rail system featured a variety of different short freight cars that were common on Japan's National Railways of the 1970s when most were first developed and used for years afterwards.
A WHAM 80000 box car with opening doors was one of the first freight cars from 1972. The doors on both sides open. Early examples have no stickers, but 80000 series stickers were added in the Super Rail Black era.
It was released in several sets in brown as well as later individually and in some sets in white and green as well.
Like other two-axle rolling stock, a spring underneath holds the couplings in tension and allows the coupling gimmick to work. It was also released in black with stickers in the five-car freight car pack. The earlier coupling hooks are clipped onto an axle molded into the rotating catch, but later hooks have the axle molded into their base and clip into holes in the receptacle.
First released in a dark blue color in one of the initial D-51 sets and later in white and yellow with Shell mark was a TAKI 45000-type tanker.
The dark blue tanker appeared with Caltex stickers in the Super Rail Black era alongside the new colors.
This open wagon was first introduced in one of the early 1974 "10s System" sets in black without stickers. It was also produced in orange and brown alongside the black car (all with stickers) in the Super Rail Black era, but black seems to be the most common.
A weight is attached to the bottom of this wagon to help keep it on the rails, as it is smaller and lighter than others.
This Koki 5000 type container car that holds four removable crate loads was released by 1978. This color variations appeared in the Shinkansen and Steam Locomotive Wide Panorama Set - usually it seems it is blue.
The containers are removable and stackable, of course, and predate the Plarail container wagon with similar removable containers.
Released first in the initial EF-66 freight set in 1979 was this cream HOKI 2200 series hopper car.