KHOWLEDGE ZONE

Have you ever stopped at a railroad crossing when a freight train rumbled by? Did you try to count the cars? Have you ever seen a high-speed passenger train whiz past? Trains are very important to transportation. Trains carry freight and people in places all over the world.

A train is made up of railroad cars hooked together and pulled by a locomotive. Locomotives are sometimes called engines. All trains run on tracks. Freight trains haul goods. Passenger trains carry people.

WHAT MOVES A TRAIN?

Locomotives push or pull railroad cars. They have powerful motors. The motors turn locomotive wheels that run on railroad tracks. Sometimes you will see three or four locomotives hooked together to pull a long freight train up a steep mountain.

Some locomotives get their power from electricity. The electricity comes from wires above the track or from a special third rail next to the track. Other locomotives get their power from diesel fuel, which is similar to the gasoline that most cars use. The kind of locomotive engines most used today are diesel-electrics. Engines that burn diesel fuel drive generators that make electricity. Powerful electric motors turn the wheels of a diesel-electric locomotive.

KINDS OF FREIGHT CARS

A freight train can have as many as 200 cars hooked together. There are special railroad cars for different kinds of freight.

The boxcar has four sides, a floor, and a roof. It looks like a box on wheels. Boxcars carry freight that has to be kept clean and dry, such as radios, television sets, and boxes of cereal.

Refrigerator cars work like your home refrigerator. They are boxcars that are cool inside. Refrigerator cars carry meat, fruit, frozen dinners, and other food that must be kept cold.

The hopper car is open on the top. Hopper cars carry coal, sand, gravel, and ore (rocks that contain metals). Hopper cars are easy to unload because they have doors on the bottom. The doors open and the coal, sand, or gravel pours out.

A flatcar has no top or sides. It has a floor on wheels. Flat cars carry lumber, steel beams, huge pieces of machinery, and other big items. Lifting machines called cranes load cargo onto flat cars. Special flatcars carry cars, boats, and trucks.

A tank car carries liquids or gases in a big, round tank that is lying on its side. Tank cars can carry milk, gasoline, or oil. Some tank cars carry dangerous chemicals.

KINDS OF PASSENGER CARS

Passenger cars have seats in rows along each side. Passengers can place small bags in a rack above the seat. Some passenger cars are made for long trips. They have seats that can be made into beds at night. Trains that carry passengers over long distances have special baggage cars to carry suitcases. They have dining cars where people can sit down and eat.

HOW DO TRAINS STAY ON THE TRACKS?

The track has two long rails made of steel. Pieces of wood or concrete called ties hold the rails in place and keep them from moving. Spikes hold the ties to the rails.

Locomotives, freight cars, and passenger cars have wheels that hold the train on the track. The wheels have a flange, a special shape that fits over the rails and keeps the train from slipping off the rails.

Railroad tracks are laid on a roadbed made of tightly packed dirt, gravel, or other material. When tracks have to go over rivers, the railroad company builds bridges. Sometimes railroad companies dig tunnels through mountains.

WHAT WERE EARLY TRAINS LIKE?

The first trains were wagons hooked together and pulled by horses, oxen, or other animals. The wagon wheels rolled over two strips made of wooden planks. Trains with wooden tracks were used as early as the 1500s to haul coal and stone. In the 1760s, iron rails replaced wooden ones.

Inventors made the first locomotives in the early 1800s. Early locomotive engines burned coal to heat water and make steam. The steam drove big pistons that turned the wheels. Inventors made bigger and better steam-engine locomotives. Steam engines drove most locomotives until the 1940s.

The first passenger cars were stagecoaches set on four railroad wheels. Then came larger cars with six wheels. In 1830, the Baltimore & Ohio became the first railroad in the United States to offer passenger service. The train was pulled by horses.

Passenger trains got better and better. In the late 1800s, a U.S. company called the Pullman Palace Car Company began making a comfortable sleeping car. Other companies made luxurious parlor cars for passengers to sit in. Train travel became very popular.

HOW HAS TRAIN TRAVEL CHANGED?

Many people traveled by train until the 1950s. Jet planes then began to replace trains as the most popular form of passenger travel. Today, most passenger trains in the United States and Canada are commuter trains. Passengers ride commuter trains twice a day between homes in the suburbs and jobs in the city. Trains continue to carry passengers between cities in Europe and in other parts of the world.

Some countries have high-speed trains. The first high-speed trains were in France and Japan. These trains can go about 260 kilometers per hour (160 miles per hour).

Engineers are working on a train that floats above its track. This type of train is called a maglev. Powerful magnets push the train a short distance above the rails as it moves along. Engineers are designing maglev trains that can travel much faster than trains on rails can.