Roller-bearings are usually put on the freight cars that need to run at passenger train speed. Greenball freight always travels fast. A greenball train carries fruits and vegetables in refrigerator cars, which are also called reefers or riffs.

At each end of a reefer are containers called bunkers. These hold ice to keep the food cool while it travels. At ordinary stations, men load ice into the bunkers by hand. But a big loading station has a giant icing machine to do the job. It rides along on its own rails, poking its great arms out and pouring tons of ice into the cars.

Suppose you are sending carloads of spinach to market. The icing machine also blows fine-chopped ice, which looks like snow, on top of the spinach to keep it fresh. But suppose you have a lot of peaches that must go from the orchard to a big city hundreds of miles away. First, the reefers have to be pre-cooled. Onto the loading platforms roll machines with big canvas funnels that fit tightly over the reefers’ doors. These are blowers that force cold air into the cars. Now the crates of fruit can be loaded quickly, and the doors sealed shut.

When fruit trains from California go across the high mountains in winter, there is danger that the reefers may get too cold. So the men lower charcoal stoves into the bunkers for the mountain trip. Then the bunkers are filled with ice when they get down into warmer country again.

Some fruits, such as bananas, have to be inspected on the road to make sure they are not spoiling. The inspectors are called messengers.

Reefers also carry meat and fish, butter, eggs, cheese and even fresh flowers.

When a reefer’s cargo is bound for a big town or city, it goes straight through, with as few stops as possible. But there are many small towns that couldn’t use up a whole carload of butter or meat before it spoiled. So the railroads have peddler cars to supply these towns with small quantities of food. The cars stop at station after station, just the way a peddler would. The storekeepers get only what they need, then the car moves on.