In addition to their many roundhouses for making light repairs to locomotives in service, the railroads own and operate hundreds of large shop plants for overhauling, rebuilding and reconditioning locomotives—commonly called "heavy repairs" or "back shop" work. The roundhouse may be likened to a first-aid station; and the repair shop plant (commonly called "railroad shops") may be likened to a completely equipped hospital for performing major operations.

Many large railroad shops are equipped to build as well as to overhaul and repair locomotives. However, most locomotives—steam, electric and Diesel-electric—are built for the railroads by manufacturing companies. Each order placed by the railroads for new locomotives is accompanied by detailed specifications and blueprints showing complete information concerning them. The manufacturing company builds the locomotives according to the railroad's specifications.

This also applies to passenger and freight cars. Some railroads are equipped to build their own cars, but many of them buy new passenger and freight cars from the car building companies.

Some railroad shops are for overhauling and repairing locomotives only; others rebuild or repair railroad cars only; while many railroad shops are equipped to rebuild and repair both locomotives and cars.

A railroad shop plant usually covers many acres and is made up of many buildings and facilities. A typical fully-equipped shop plant may include a locomotive erecting shop; a machine shop; a blacksmith shop; a power house; a boiler shop; a tank shop; a tool room; a tin, copper and pipe shop; an oil house; an electric shop; a foundry; a planing mill; a paint shop; a storeroom and storage yards.

Railroad shops which are equipped for building or reconditioning freight and passenger cars as well as locomotives, may also include a wood mill, a wheel shop, and an upholstery shop. Several miles of railway tracks connect and extend through some of these buildings and through storage yards and grounds.

Among the most impressive features of the locomotive erecting shop are the huge overhead electric cranes which move back and forth, above the main floor of the shop, performing prodigious feats of strength. These cranes are capable of picking up and carrying the heaviest locomotives from one end of the shop to the other. The dark object extending across the shop room in the upper left side of the picture is an electric crane.

The work to be done on each locomotive is covered by a shop order. A definite time schedule is worked out, and a requisition is sent to the Purchasing and Stores Department for any materials or parts which will be required to complete the job.

The job of overhauling and repairing the engine may require several weeks. The shop order may call for extensive replacements of worn-out parts such as flues, wheels or tires, and the repair or replacement of valves, brakes, springs, bolts, pipes, and so on. When the job is finished, the locomotive will be painted and put in condition for operation.

Some locomotive shops employ hundreds of workmen, some employ thousands. Railway shop forces include foremen, inspectors, boilermakers and boilermakers' helpers, machinists and machinists' helpers, blacksmiths and blacksmiths' helpers, lathe operators, electric drill operators, riveters, carpenters, painters, engine cleaners, sandpipemen, crane operators, motor-truck and tractor operators, laborers, watchmen, and many other workers, skilled and unskilled.

Approximately one out of every four persons employed by the American railroads is engaged in keeping locomotives and cars in good condition.

The picture shows the interior of a locomotive erecting shop. In the foreground workmen are engaged in reconditioning a big locomotive. The engine has been dismantled and given a complete overhauling; many old parts have been replaced with new ones, and the men are now seen putting the finishing touches to the engine before returning it to road service. (This is the same type of locomotive as is shown in the Roundhouse and the Turntable photo.) The men on the floor in the foreground are working on the locomotive cylinder. The man on the front-end platform is opening or closing the smokebox door. Other workmen are repainting the locomotive.