Pennsylvania Power and Light "D" at the Railroad Museum of Pennsylvania
A fireless locomotive is a type of locomotive which uses reciprocating engines powered from a reservoir of compressed air or steam, which is filled at intervals from an external source. They offer advantages over conventional steam locomotives of lower cost per unit, cleanliness, and decreased risk from fire or boiler explosion; these are counterbalanced by the need for a source to refill the locomotive, and by the limited range afforded by the reservoir.
Typical usage was in industrial switching where a conventional locomotive was too noxious or risky, such as in a mine or a food or chemical factory; they also saw use where the source of air or steam was readily available.
An early application of the fireless locomotive was to street tramways in the USA. Emile Lamm developed two types of fireless locomotive, one using ammonia and the other using stored steam. Lamm founded two companies, Ammonia & Thermo-Specific Propelling Company of America in 1872 and (with Sylvester L. Langdon) Lamm Fireless Engine Company in 1874.Lamm's fireless engines were briefly popular, both in the USA and in France, but were soon displaced by electric trams. The French locomotives were built in association with Leon Francq, under the name Lamm & Francq.
The fireless system then gained a new lease of life for industrial shunting locomotives. Any factory which possessed a stationary boiler could use it to charge a fireless steam locomotive for internal shunting operations. Fireless shunting locomotives became especially popular in Germany and some remained in service into the 1960s. Fireless industrial shunters were usually of the 0-4-0 or 0-6-0 wheel arrangement but some 0-8-0s were built, by companies including Heisler. Pennsylvania Power and Light "D", in the gallery below, is an example of an 0-8-0 fireless Heisler locomotive.
The Swiss company, DLM, was recently (2012) trying to promote the fireless steam locomotive as an environmentally-friendly alternative to the diesel locomotive for shunting. DLM claims that diesel shunters typically spend 75% of their working time with the engine idling.
A fireless steam locomotive is similar to a conventional steam locomotive, but has a reservoir, known as a steam accumulator, instead of a boiler. This reservoir is charged with superheated water under pressure from a stationary boiler. The engine works like a conventional steam engine using the high pressure steam above the water in the accumulator. As the steam is used and pressure drops, the superheated water boils, replacing the used steam. The locomotive can work like this until the pressure has dropped to a minimum useful level or the water runs out, after which it must be recharged.
European fireless steam locomotives usually have the cylinders at the back, while American ones often have the cylinders at the front, as in a conventional locomotive. Major builders of fireless steam locomotives in the UK included Andrew Barclay and W.G. Bagnall.
The first locomotive to run on compressed air was built in 1890, and by 1895, the basic principles of efficient compressed air engines had been developed. A particularly important engineering breakthrough was the development of the reducing and stop valve which maintains a uniform pressure of air to the engine, even as the pressure in the storage tank reduces with use. Compressed air locomotives have been used for many years, mainly in mines, but have also been used on tramways. (See Mekarski system)
Several hybrid locomotives have been built that have either used a fire for part of the time, e.g., Fowler's Ghost of London's Metropolitan in 1861, or have used a fire to superheat stored steam, such as the Receiver Locomotives built by Sentinel Waggon Works. None has been a success.
Most fireless locomotives have been of 0-4-0 or 0-6-0 wheel arrangement but there have been some 0-8-0 and even a few 0-10-0. Some gauge 0-10-0 fireless locomotives from the German company Henschel were used in the construction of the Baghdad Railway, probably to avoid the risk of carbon monoxide poisoning during the boring of tunnels.
Steam traction became obsolete in the 1940s and was largely replaced by diesel or electric traction. However, fireless steam has its merits, especially where there is an abundant cheap source of steam, such as in industrial sites, at thermal power stations or refuse incineration plants, where fireless steam locomotives are used for shunting at very low cost.
As they do not emit any exhaust except steam, they can shunt into buildings without endangering the workforce with noxious fumes.
Considering that shunting locomotives are typically working for only about 10% of the time, 90% waiting for work; a diesel locomotive, idling most of the time, burns too much fuel producing nothing. A well insulated modern steam accumulator can preserve pressure over many hours. Thus the operating cost of a fireless steam shunter can be far less than that of a comparable diesel.
Fireless locomotives are also safer to operate than conventional steam locomotives, aside from the elimination of ignition hazards. The primary cause of a locomotive boiler explosion is the depletion of boiler water, through inattention or excessive use, exposing the crown sheet directly to the flames of the firebox without the cooling effect of the water covering, weakening it to the point of failure. A fireless locomotive eliminates this danger--if it runs out of sufficient water, it simply ceases to move--although precautions must be taken as with any other pressure vessel. Furthermore, they did not require careful monitoring of water levels and boiler pressure, nor careful distribution of coal in the firebox for efficient combustion, and thus could be operated by less-skilled staff, not requiring a fully qualified locomotive engineer and fireman.
Several locomotive builders produced fireless engines throughout the 20th century. Meiningen Steam Locomotive Works was still building them in the 1980s. Some fireless locomotives are in daily use even in 2016. One example is the large coal-fired power station in Mannheim where coal is delivered by rail in long trains of self-discharging hopper wagons. Three fireless engines are used to shunt the hoppers on the premises of the power station.
East Germany, preferring to use its abundant supply of lignite to imported fuel, used fireless engines extensively. A series of 200 fireless locomotives was built at Raw Meiningen as late as the 1980s.
In 2017, Semboro sugar mill in Jember, East Java used two fireless locomotives due to the presence of flammable bagasse. The locos were built by Orenstein & Koppel in Germany in 1928 and 1929 and were used for shunting inside the mill.
In 2011, Pagottan sugar mill in Madiun, also in East Java used three Luttermöller axle locomotives, numbered 6, 7 and 8. These were conventional steam locomotives that were converted to fireless operation in 2011.
Switzerland had used older fireless engines in industry, such as breweries. In 2010, the steam company Dampflokomotiv- und Maschinenfabrik DLM refurbished two locomotives of the German Meiningen type and modernised them for use on sidings. 
Numerous examples have been preserved across the world.
The German popflock.com resource has a list of steam accumulator locomotives preserved in that country. It includes over 100 preserved fireless engines, 8 of them operational.
One notable example is "Lord Ashfield" (Andrew Barclay works no. 1989 of 1930) at the Museum of Science and Industry in Manchester. It ran in limited service in the 1990s sharing a steam supply with the stationary exhibits.
The Ayrshire Railway Preservation Group has rebuilt its Andrew Barclay 0-4-0 fireless locomotive (Works Number 1952 of 1928). The engine returned to service in 2015, and operates as part of a demonstration freight train.
The North Carolina Transportation Museum in Spencer has a fireless steam locomotive, the North Carolina Power and Light #3 0-4-0.
Three National Cash Register 0-4-0 fireless switchers have been preserved: one at Carillon Historical Park in Dayton, Ohio, one at the Southeastern Railway Museum in Duluth, Georgia, and one at the National Museum of Transportation in Kirkwood, Missouri.
Pennsylvania Power and Light "D", an 0-8-0 switcher, is preserved in the Railroad Museum of Pennsylvania.
Union Electric Company 4, a 0-4-0 is preserved in the Illinois Railway Museum of Union Illinois.
Cleveland Electric Illuminating Company, an 0-6-0 built by the H.K. Porter Company, is preserved in the Mad River and NKP Railroad Museum in Bellevue, Ohio
North American Rayon Company, 1936 H.K. Porter Company, 0-6-0F Fireless Locomotive, Elizabethton, Tennessee, U.S.A The locomotive was called "The Pot". This rare fireless locomotive was built in 1936 for the North American Rayon Company(N.A.R.C.) of Elizabethton, Tennessee. Its steam was supplied from a large reservoir located inside of the N.A.R.C. plant. Fireless locomotives were used in industrial situations where there was an increased risk of fire. N.A.R.C. made Rayon, which is a highly flammable material. The locomotive retired from service in 1992 and it is possibly the last fireless locomotive to be retired from service in the USA. N.A.R.C. shutdown in 2000 and donated "The Pot" to the Carter County Chamber of Commerce and is on public display in Elizabethton, TN. 
Pennsylvania Power and Light "D" at the Railroad Museum of Pennsylvania