Originally flatcars fitted with cabins or modified box cars, they later became purpose-built with projections above or to the sides of the car to allow crew to observe the train from shelter. The caboose also served as the conductor's office, and on long routes included accommodation and cooking facilities.

A similar railroad car design, the brake van, was used on British and Commonwealth railways. These provided the additional function of serving as a supplemental braking system for trains not fitted with a continuous braking system, and keeping chain couplings taut.

Cabooses were used on every freight train until the 1980s, when safety laws requiring the presence of cabooses and full crews were relaxed. Developments in monitoring and safety technology such as lineside defect detectors and end-of-train devices resulted in crew reductions and the phasing out of caboose cars. Nowadays, they are generally only used on rail maintenance or hazardous materials trains, or on heritage and tourist railroads.

Use of cabooses began in the 1830s, when railroads housed trainmen in shanties built onto boxcars or flatcars.[1] The caboose provided the train crew with a shelter at the rear of the train. The crew could exit the train for switching or to protect the rear of the train when stopped. They also inspected the train for problems such as shifting loads, broken or dragging equipment, and hot boxes (overheated axle bearings, a serious fire and derailment threat). The conductor kept records and handled business from a table or desk in the caboose. For longer trips, the caboose provided minimal living quarters, and was frequently personalized and decorated with pictures and posters.

Early cabooses were nothing more than flat cars with small cabins erected on them, or modified box cars. The standard form of the American caboose had a platform at either end with curved grab rails to facilitate train crew members' ascent onto a moving train. A caboose was fitted with red lights called markers to enable the rear of the train to be seen at night. This has led to the phrase "bringing up the markers" to describe the last car on a train. These lights were officially what made a train a "train",[2] and were originally lit with oil lamps. With the advent of electricity, later caboose versions incorporated an electrical generator driven by belts coupled to one of the axles, which charged a lead-acid storage battery when the train was in motion. The addition of the cupola, a lookout post atop the car, was introduced in 1863.[3]

Coal or wood was originally used to fire a cast-iron stove for heat and cooking, later giving way to a kerosene heater. Now rare, the old stoves can be identified by several essential features. They were without legs, bolted directly to the floor, and featured a lip on the top surface to keep pans and coffee pots from sliding off. They also had a double-latching door, to prevent accidental discharge of hot coals caused by the rocking motion of the caboose.

Cabooses are nonrevenue equipment and were often improvised or retained well beyond the normal lifetime of a freight car. Tradition on many lines held that the caboose should be painted a bright red, though on many lines it eventually became the practice to paint them in the same corporate colors as locomotives. The Kansas City Southern Railway was unique in that it bought cabooses with a stainless steel car body, and so was not obliged to paint them.

Until the 1980s, laws in the United States and Canada required all freight trains to have a caboose and a full crew, for safety. Technology eventually advanced such that the railroads, in an effort to save money and reduce crew members, stated that a caboose was unnecessary, since bearings were improved and lineside detectors were used to detect hot boxes, and better-designed cars avoided problems with the loads. The railroads also claimed a caboose was a dangerous place, as slack run-ins could hurl the crew from their places and even dislodge weighty equipment.

Railroads proposed the end-of-train device (EOT or ETD) as an alternative. An ETD could be attached to the rear of the train to detect the train's air brake pressure and report any problems to the locomotive. The ETD also detects movement of the train upon start-up and radios this information to the engineers so they know all of the slack is out of the couplings and additional power could be applied. The machines also have blinking red lights to warn following trains that a train is ahead. With the introduction of the ETD, the conductor moved up to the front of the train with the engineer.

A 1982 Presidential Emergency Board convened under the Railway Labor Act directed United States railroads to begin eliminating caboose cars where possible to do so.[4] A legal exception was the state of Virginia, which had a 1911 law mandating cabooses on the ends of trains, until the law's final repeal in 1988. With this exception aside, year by year, cabooses started to fade away.[5] Very few cabooses remain in operation today, though they are still used for some local trains where it is convenient to have a brakeman at the end of the train to operate switches, on long reverse movements, and are also used on trains carrying hazardous materials.

CSX Transportation is one of the only Class 1 railroads that still maintains a fleet of modified cabooses for regular use. Employed as "shoving platforms" at the rear of local freight trains which must perform long reverse moves or heavy switching, these are generally rebuilt bay-window cabooses with their cabin doors welded shut (leaving their crews to work from the rear platform). BNSF also maintains a fleet of former wide-vision cabooses for a similar purpose, and in 2013 began repainting some of them in heritage paint schemes of BNSF's predecessor railroads.

During the '60s I was a conductor on the C&NW. One day late in the summer of 1863 I received orders to give my caboose to the conductor of a construction train and take an empty boxcar to use as a caboose. This car happened to have a hole in the roof about two feet square. I stacked the lamp and tool boxes under the perforation end and sat with my head and shoulders above the roof ... (Later) I suggested putting a box around the hole with glass in, so I could have a pilot house to sit in and watch the train.

The position of the cupola varied. In most eastern railroad cabooses, the cupola was in the center of the car, but most western railroads preferred to put it toward the end of the car. Some conductors preferred to have the cupola toward the front, others liked it toward the rear of the train, and some just did not care. ATSF conductors could refuse to be assigned to a train if they did not have their cabooses turned to face the way they preferred. However, this would be a rare union agreement clause that could be used, but was not a regular issue.

The classic idea of the "little red caboose" at the end of every train came about when cabooses were painted a reddish brown; however, some railroads (UP, and NKP, for example) painted their cabooses yellow or red and white. The most notable was the Santa Fe which in the 1960s started a rebuild program for their cabooses in which the cars were painted bright red with an eight-foot-diameter Santa Fe cross herald emblazoned on each side in yellow. Some railroads, chiefly the Wabash Railway, Norfolk and Western and Illinois Central Gulf, also built or upgraded cabooses with streamlined cupolas for better aerodynamics and to project a more modern image.

In a bay window caboose, the crew monitoring the train sits in the middle of the car in a section of wall that projects from the side of the caboose. The windows set into these extended walls resemble architectural bay windows, so the caboose type is called a bay window caboose. This type afforded a better view of the side of the train and eliminated the falling hazard of the cupola.[citation needed] It is thought to have first been used on the Akron, Canton and Youngstown Railroad in 1923, but is particularly associated with the Baltimore and Ohio Railroad, which built all of its cabooses in this design starting from an experimental model in 1930. The bay window gained favor with many railroads because it eliminated the need for additional clearances in tunnels and overpasses.

In the extended-vision or wide-vision caboose, the sides of the cupola project beyond the side of the car body. Rock Island created some of these by rebuilding some standard cupola cabooses with windowed extensions applied to the sides of the cupola itself, but by far, the greatest number have the entire cupola compartment enlarged. This model was introduced by the International Car Company and saw service on most U.S. railroads. The expanded cupola allowed the crew to see past the top of the taller cars that began to appear after World War II, and also increased the roominess of the cupola area.

Additionally, Monon Railroad had a unique change to the extended-vision cabooses. They added a miniature bay to the sides of the cupola to enhance the views further. This created a unique look for their small fleet. Seven of the eight Monon-built cabooses have been saved. One was scrapped after an accident in Kentucky. The surviving cars are at the Indiana Transportation Museum (operational), the Indiana Railway Museum (operational), the Kentucky Railway Museum (fire damaged), and the Bluegrass Railroad Museum (unrestored but servicable). The remaining three are in private collections.

A transfer caboose looks more like a flat car with a shed bolted to the middle of it than it does a standard caboose. It is used in transfer service between rail yards or short switching runs, and as such, lacks sleeping, cooking or restroom facilities. The ends of a transfer caboose are left open, with safety railings surrounding the area between the crew compartment and the end of the car.

A recent variation on the transfer caboose is the "pushing" or "shoving" platform. It can be any railcar where a brakeman can safely ride for some distance to help the engineer with visibility at the other end of the train. Flatcars and covered hoppers have been used for this purpose, but often the pushing platform is a caboose that has had its windows covered and welded shut and permanently locked doors. CSX uses former Louisville & Nashville short bay window cabooses and former Conrail waycars as pushing platforms.

Drover's cabooses looked more like combine cars than standard cabooses. The purpose of a drover's caboose was much more like a combine, as well. On longer livestock trains in the American West, the drover's caboose is where the livestock's handlers would ride between the ranch and processing plant. The train crew rode in the caboose section while the livestock handlers rode in the coach section. Drover's cabooses used either cupolas or bay windows in the caboose section for the train crew to monitor the train. The use of drover's cars on the Northern Pacific Railway, for example, lasted until the Burlington Northern Railroad merger of 1970. They were often found on stock trains originating in Montana.

Railroad historian David L. Joslyn (a retired Southern Pacific Railroad draftsman) has traced the possible root of "caboose" to the obsolete Low German word Kabhuse, a small cabin erected on a sailing ship's main deck. This was absorbed into Middle Dutch and entered the Dutch languagecirca 1747 as kabhuis, the compartment on a ship's main deck in which meals were prepared.

Eighteenth century French naval records also make reference to a cambose or camboose, which described both the food preparation cabin on a ship's main deck and its stove. Camboose may have entered English through American sailors who had come into contact with their French allies during the American Revolution. It was already in use in U.S. naval terminology by the 1797 construction of the USS Constitution, whose wood-burning food preparation stove is known as the camboose.[7] In modern French, cambuse can refer both to a ship's storeroom and to the North-American railcar.

Camboose as a cook shack was in use in English at least by 1805, when it was used in a New York Chronicle article cited in the New English Dictionary describing a New England shipwreck, which reported that "[Survivor] William Duncan drifted aboard the canboose [sic]."[8] As the first railroad cabooses were wooden shanties erected on flat cars as early as the 1830s,[9] they would have resembled the cook shack on a ship's deck.

The earliest known printed record of "caboose" used to describe the railcar appeared in 1859 in court records in conjunction with a lawsuit filed against the New York and Harlem Railway.[8]

Like many nautical terms this one may have come from Danish. The Danish word for a galley is "kabys". The Danish "y" is pronounced like the English "oo", thus "caboose". The plural is "kabyser".

There is some disagreement on what constitutes the proper plural form of the word "caboose." Similar words, like goose (pluralized as "geese") and moose (pluralized as "moose"), differ. The most common pluralization of caboose is "cabooses," with some arguing it should remain "caboose".

It was common for railroads to officially refer to cabooses as "cabin cars."

Although the caboose has largely fallen out of use, some are still retained by railroads in a reserve capacity. These cabooses are typically used in and around railyards. Other uses for the caboose include "special" trains, where the train is involved in some sort of railway maintenance, or as part of survey trains that inspect remote rail lines after natural disasters to check for damage. Others have been modified for use in research roles to investigate complaints from residents or business owners regarding trains in certain locations. Finally, some are coupled to trains for special events, including historical tours.

Cabooses have also become popular for collection by railroad museums and for city parks and other civic uses, such as visitor centers. Several railroad museums roster large numbers of cabooses, including the Illinois Railway Museum with 19 examples and the Western Pacific Railroad Museum at Portola, California, with 17. Many shortline railroads still use cabooses today. Large railroads also use cabooses as "shoving platforms" or in switching service where it is convenient to have crew at the rear of the train.

Cabooses have been reused as vacation cottages,[10] garden offices in private residences, and as portions of restaurants. Also, caboose motels have appeared, with the old cars being used as cabins.[11]