Besides the ordinary cars that do ordinary jobs, railroads have some cars that have been made for special purposes.

A medical car is really a small traveling hospital. It goes along with construction crews when they have a big job to do far from a station. A trained nurse has her office in the car. She can take care of small injuries or give first aid until a doctor arrives.

One special car looks like a load of big sausages. It is really a sort of boxcar frame into which long, heavy pipes have been fitted so that they wind back and forth. The pipes carry a load of helium gas. Helium is used in balloons and blimps, because it is very light and it can’t catch fire. Even when this car is fully loaded with all the gas that can be squeezed into the pipes, it weighs only a ton more than an empty car. Most loaded freight cars weigh between forty and eighty tons.

Sometimes a factory wants to ship a very tall machine by freight. So the railroad has it loaded onto an underslung flat car that looks as if it had had a bite taken out of its middle. It’s called a depressed center car.

But still the machine may stick up too high to go through underpasses. Then a special department gets to work figuring out what to do. Men who know every mile of track work out a route that has no low underpasses. This sometimes means that the machine will make a dozen detours before it is delivered.

Circus cars are sometimes just flat cars which carry the animals’ cages. But some of them are specially built like stables, with stalls and a storage place for food. Fancy race horses ride in padded stable cars, too.

A pickle car is made of six separate wooden tanks. Men at the pickle works fill them with cucumbers and brine. Then the car delivers them at the factory to be bottled.