Chimney (locomotive)
Encyclopedia
The chimney of a steam locomotive
is a part of the exhaust system
which helps in the creation of draught through the boiler and carries the exhaust steam and smoke clear of the driver's line of sight. Different designs also helped create distinctive aesthetic looks for different companies and designers.
at the leading end of the locomotive, furthest away from the driver's cab.
"Stovepipe" chimney on the 19th century LSWR, or the copper-capped chimneys on the Great Western Railway
.
The look of the chimney was also affected on locomotives that burned wood or turf, or ran through areas of high fire-risk, by the addition of a large spark arrester
which were known as "balloon stacks" in North America.
In order to achieve these functions, the internal dimensions of the chimney were critical, as well as its positioning relative to the blastpipe
, but this was not widely understood until well into the 20th century.
As locomotive boilers grew larger, the space available for chimneys was reduced, as they still had to fit within the same loading gauge
. This reduced their effectiveness at keeping the exhaust gases away from the driver's line of sight, and as a result locomotives had to be fitted with devices such as smoke deflectors
.
, working at Swindon
on the GWR
, formulated a simple equation for calculating the ideal dimensions for chimneys which worked well for the early years of the 20th century, but soon become outdated as engine powers increased.
André Chapelon
in France continued to work on chimney dimensions, and studied them in conjunction with blastpipe dimensions as a complete Steam locomotive exhaust system
, such as his famous Kylchap
system as fitted to many locomotive classes worldwide.
Even after the end of commercial steam in most of the developed world, the Argentinean engineer Livio Dante Porta
continued to work on developing steam locomotive exhaust systems including refining equations to give better chimney dimensions.
Steam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...
is a part of the exhaust system
Steam locomotive exhaust system
The Steam locomotive exhaust system consists of those parts of a steam locomotive which together discharge exhaust steam from the cylinders in order to increase the draught through the fire...
which helps in the creation of draught through the boiler and carries the exhaust steam and smoke clear of the driver's line of sight. Different designs also helped create distinctive aesthetic looks for different companies and designers.
Position
The chimney was usually located above the smokeboxSmokebox
A smokebox is one of the major basic parts of a Steam locomotive exhaust system. Smoke and hot gases pass from the firebox through tubes where they pass heat to the surrounding water in the boiler. The smoke then enters the smokebox, and is exhausted to the atmosphere through the chimney .To assist...
at the leading end of the locomotive, furthest away from the driver's cab.
Construction
In Great Britain, and British built locomotives, chimneys were usually of cast-iron construction, as it was found to last longer than fabricated types. Fabricated construction was more common where spark arrestors were used, due to the difficulty of casting this complicated feature.Aesthetics
Many designers or railway companies had their own distinctive style, such as the William Adams'William Adams (locomotive engineer)
William Adams was the Locomotive Superintendent of the North London Railway from 1858 to 1873; the Great Eastern Railway from 1873 until 1878 and the London and South Western Railway from then until his retirement in 1895...
"Stovepipe" chimney on the 19th century LSWR, or the copper-capped chimneys on the Great Western Railway
Great Western Railway
The Great Western Railway was a British railway company that linked London with the south-west and west of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament in 1835 and ran its first trains in 1838...
.
The look of the chimney was also affected on locomotives that burned wood or turf, or ran through areas of high fire-risk, by the addition of a large spark arrester
Spark arrester
A spark arrestor is any device which prevents the emission of flammable debris from combustion sources, such as internal combustion engines, fireplaces, and wood burning stoves. Spark arrestors play a critical role in the prevention of wildland fire and ignition of explosive atmospheres...
which were known as "balloon stacks" in North America.
Function and internal design
The chimney served 2 main purposes:- To lift the exhaust gases (smokeSmokeSmoke is a collection of airborne solid and liquid particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-product of fires , but may also be used for pest...
and steamSteamSteam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. In common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air...
) above the locomotive, keeping them clear of the driver's view of the track ahead. - Together with the blastpipeBlastpipeThe blastpipe is part of the exhaust system of a steam locomotive that discharges exhaust steam from the cylinders into the smokebox beneath the chimney in order to increase the draught through the fire.- History :...
it created a vacuum in the smokeboxSmokeboxA smokebox is one of the major basic parts of a Steam locomotive exhaust system. Smoke and hot gases pass from the firebox through tubes where they pass heat to the surrounding water in the boiler. The smoke then enters the smokebox, and is exhausted to the atmosphere through the chimney .To assist...
which then induced a draught through the boiler flues from the fireboxFireboxIn a steam engine, the firebox is the area where the fuel is burned, producing heat to boil the water in the boiler. Most are somewhat box-shaped, hence the name.-Railway locomotive firebox :...
.
In order to achieve these functions, the internal dimensions of the chimney were critical, as well as its positioning relative to the blastpipe
Blastpipe
The blastpipe is part of the exhaust system of a steam locomotive that discharges exhaust steam from the cylinders into the smokebox beneath the chimney in order to increase the draught through the fire.- History :...
, but this was not widely understood until well into the 20th century.
As locomotive boilers grew larger, the space available for chimneys was reduced, as they still had to fit within the same loading gauge
Loading gauge
A loading gauge defines the maximum height and width for railway vehicles and their loads to ensure safe passage through bridges, tunnels and other structures...
. This reduced their effectiveness at keeping the exhaust gases away from the driver's line of sight, and as a result locomotives had to be fitted with devices such as smoke deflectors
Smoke deflectors
Smoke deflectors are vertical plates attached to the front of a steam locomotive on each side of the smokebox. They are designed to lift smoke away from the locomotive at speed so that the driver has better visibility unimpaired by drifting smoke....
.
Development
George Jackson ChurchwardGeorge Jackson Churchward
George Jackson Churchward CBE was Chief Mechanical Engineer of the Great Western Railway in the United Kingdom from 1902 to 1922.-Early career:...
, working at Swindon
Swindon
Swindon is a large town within the borough of Swindon and ceremonial county of Wiltshire, in South West England. It is midway between Bristol, west and Reading, east. London is east...
on the GWR
GWR
GWR is an acronym that can stand for:* Great Western Railway , the name of several different railway operators* The Gloucestershire Warwickshire Railway — a heritage railway that has taken the initials of the former Great Western Railway Company* Great Whipsnade Railway* GWR Group, former...
, formulated a simple equation for calculating the ideal dimensions for chimneys which worked well for the early years of the 20th century, but soon become outdated as engine powers increased.
André Chapelon
André Chapelon
André Chapelon was a noted French mechanical engineer and designer of advanced steam locomotives. Engineer of Ecole Centrale Paris, he was one of very few locomotive designers who brought a rigorous scientific method to their design, and he sought to apply up-to-date knowledge and theories in...
in France continued to work on chimney dimensions, and studied them in conjunction with blastpipe dimensions as a complete Steam locomotive exhaust system
Steam locomotive exhaust system
The Steam locomotive exhaust system consists of those parts of a steam locomotive which together discharge exhaust steam from the cylinders in order to increase the draught through the fire...
, such as his famous Kylchap
Kylchap
The Kylchap steam locomotive steam locomotive exhaust system was designed and patented by the famous French steam engineer André Chapelon, using a second-stage nozzle designed by the Finnish engineer Kyösti Kylälä and known as the Kylälä spreader; thus the name KylChap for this design.The Kylchap...
system as fitted to many locomotive classes worldwide.
Even after the end of commercial steam in most of the developed world, the Argentinean engineer Livio Dante Porta
Livio Dante Porta
Livio Dante Porta was an Argentine steam locomotive engineer. He is particularly remembered for his innovative modifications to existing locomotive systems in order to obtain higher performance, energy efficiency and reduced pollution. He developed the Kylpor and Lempor exhaust systems...
continued to work on developing steam locomotive exhaust systems including refining equations to give better chimney dimensions.