Track pan
Encyclopedia
A track pan or water trough (British
terminology) is a device to enable a steam railway locomotive to replenish its water supply while in motion. It consists of a long trough filled with water, lying along a flat stretch of railroad/railway track
between the rails.
When a steam locomotive passes at speed over the trough, its water scoop can be lowered, and the speed of forward motion forces water into the scoop, up the scoop pipe and into the tanks or locomotive tender.
s consume considerable volumes of water, and the tender or side tanks need to be replenished at intervals. Where long distance non-stop running is contemplated, there is a need to replenish without stopping.
John Ramsbottom
, a Victorian locomotive engineer, devised the water trough/track pan to meet this need. It is a very long (several hundred yards) open-ended shallow trough laid between the rails. A nearby water source is needed to recharge the trough as passing trains take water. The entire length of the installation must be on level track, with a short section of rising track at each end to keep the water in. As trains needed to be moving at some speed to pick-up enough water, a suitable separation between trough locations and commercial stopping points is essential.
The first installation was about October 1860 by the London and North Western Railway
at Mochdre, Conwy
on its North Wales Coast
(or Chester and Holyhead
) line.
mechanism. The scoop feeds into a vertical pipe that discharges into the water tank.
The scoop needs to be lowered at speed at the correct location - shortly before the start of the trough - and raised again when either the tank is full, or at the end of the trough. Lineside indicators are provided to assist engine crews in determining the location; in the UK it was a large white rectangular board with a black horizontal zigzag marking. On American railroads, illuminated trackside signals were employed for night-time usage, to indicate the start and approaching end of the track pan.
Venting on the tender needed to be free to allow a high release of expelled air from the tank.
railway in Britain, two streamlined trains with "Coronation" class locomotives happened to pass each other at a water trough when one of the trains was taking on water. The other train suffered broken windows due to lumps of tender coal scattered by the spray and the complaints from drenched passengers caused the management to retimetable the trains to ensure this could not happen again.
The considerable water spray made track maintenance difficult, and the physical trough equipment limited access for packing sleepers
, exacerbating the problem. In very cold weather the water would freeze, preventing water pick-up, unless a heating apparatus was installed.
Track pans normally took a while to fill up after being used, so they could not be used immediately by a close-following train. They were also expensive to maintain, generally requiring a pumping station
, a lot of plumbing, and an employee or two to maintain. They were thus only justified on a railroad with a high traffic volume. In the United States, several big eastern railroads used them, primarily the New York Central and Pennsylvania Railroad
.
In Britain
, they could be found on all main lines, except on the Southern Railway.
s were introduced in the United Kingdom by British Railways in the 1950s, working alongside steam traction until 1968. Passenger vehicles were heated by steam from the locomotive boiler at that time, and the early diesel locomotives were provided with auxiliary boilers to provide the steam. Locomotives intended for long non-stop runs (such as the Class 40
and Class 55
) were fitted with water scoops to allow them to replenish the steam generator's water supply from troughs/pans. The withdrawal of steam traction and the introduction of rolling stock with electric rather than steam heating removed the need for such equipment on later types and scoop-equipped locomotives had their scoops removed.
The practice of drafting water in this way gave rise to the American expression, "Jerkwater Town," used generally to indicate a small town or out-of-the-way place. If a town were sizable, it would have a water tank for which the train would stop to take on water. If the town didn't rate a water tank, it would be forced to "jerk" water while moving to refill the engine's tender.
British English
British English, or English , is the broad term used to distinguish the forms of the English language used in the United Kingdom from forms used elsewhere...
terminology) is a device to enable a steam railway locomotive to replenish its water supply while in motion. It consists of a long trough filled with water, lying along a flat stretch of railroad/railway track
Rail tracks
The track on a railway or railroad, also known as the permanent way, is the structure consisting of the rails, fasteners, sleepers and ballast , plus the underlying subgrade...
between the rails.
When a steam locomotive passes at speed over the trough, its water scoop can be lowered, and the speed of forward motion forces water into the scoop, up the scoop pipe and into the tanks or locomotive tender.
Track equipment
Main line steam locomotiveSteam 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...
s consume considerable volumes of water, and the tender or side tanks need to be replenished at intervals. Where long distance non-stop running is contemplated, there is a need to replenish without stopping.
John Ramsbottom
John Ramsbottom (engineer)
John Ramsbottom was an English mechanical engineer who created many inventions for railways, including the piston ring, the Ramsbottom safety valve, the displacement lubricator, and the water trough.- Biography :...
, a Victorian locomotive engineer, devised the water trough/track pan to meet this need. It is a very long (several hundred yards) open-ended shallow trough laid between the rails. A nearby water source is needed to recharge the trough as passing trains take water. The entire length of the installation must be on level track, with a short section of rising track at each end to keep the water in. As trains needed to be moving at some speed to pick-up enough water, a suitable separation between trough locations and commercial stopping points is essential.
The first installation was about October 1860 by the London and North Western Railway
London and North Western Railway
The London and North Western Railway was a British railway company between 1846 and 1922. It was created by the merger of three companies – the Grand Junction Railway, the London and Birmingham Railway and the Manchester and Birmingham Railway...
at Mochdre, Conwy
Mochdre, Conwy
Mochdre is a village to the west of Colwyn Bay in Conwy County Borough, north Wales. Originally part of the Municipal Borough of Colwyn Bay prior to local government reorganisation in April 1974, it is now a separate community , whose population at the 2001 census was 1,862.- Origin of the name...
on its North Wales Coast
North Wales Coast Line
The North Wales Coast Line is the railway line from Crewe to Holyhead. Virgin Trains consider their services along it to be a spur of the West Coast Main Line. The first section from Crewe to Chester was built by the Chester and Crewe Railway and absorbed by the Grand Junction Railway shortly...
(or Chester and Holyhead
Chester and Holyhead Railway
The Chester and Holyhead Railway was incorporated out of a proposal to link Holyhead, the traditional port for the Irish Mail, with London by way of the existing Chester and Crewe Railway, and what is now the West Coast Main Line...
) line.
Locomotive equipment
A scoop is fitted to the underside of the locomotive's tender (or the locomotive itself in the case of tank locomotives) in such a way that it can be raised or lowered, by a screw mechanism or a compressed airCompressed air
Compressed air is air which is kept under a certain pressure, usually greater than that of the atmosphere. In Europe, 10 percent of all electricity used by industry is used to produce compressed air, amounting to 80 terawatt hours consumption per year....
mechanism. The scoop feeds into a vertical pipe that discharges into the water tank.
The scoop needs to be lowered at speed at the correct location - shortly before the start of the trough - and raised again when either the tank is full, or at the end of the trough. Lineside indicators are provided to assist engine crews in determining the location; in the UK it was a large white rectangular board with a black horizontal zigzag marking. On American railroads, illuminated trackside signals were employed for night-time usage, to indicate the start and approaching end of the track pan.
Venting on the tender needed to be free to allow a high release of expelled air from the tank.
Operational considerations
Taking water at speed results in considerable spray behind the scoop; this risks drenching passengers in the leading vehicles, and in Great Britain it was customary for the guard or other traincrew to warn passengers in the first coach to keep the windows closed. In one incident on the LMSLondon, Midland and Scottish Railway
The London Midland and Scottish Railway was a British railway company. It was formed on 1 January 1923 under the Railways Act of 1921, which required the grouping of over 120 separate railway companies into just four...
railway in Britain, two streamlined trains with "Coronation" class locomotives happened to pass each other at a water trough when one of the trains was taking on water. The other train suffered broken windows due to lumps of tender coal scattered by the spray and the complaints from drenched passengers caused the management to retimetable the trains to ensure this could not happen again.
The considerable water spray made track maintenance difficult, and the physical trough equipment limited access for packing sleepers
Railroad tie
A railroad tie/railway tie , or railway sleeper is a rectangular item used to support the rails in railroad tracks...
, exacerbating the problem. In very cold weather the water would freeze, preventing water pick-up, unless a heating apparatus was installed.
Track pans normally took a while to fill up after being used, so they could not be used immediately by a close-following train. They were also expensive to maintain, generally requiring a pumping station
Pumping station
Pumping stations are facilities including pumps and equipment for pumping fluids from one place to another. They are used for a variety of infrastructure systems, such as the supply of water to canals, the drainage of low-lying land, and the removal of sewage to processing sites.A pumping station...
, a lot of plumbing, and an employee or two to maintain. They were thus only justified on a railroad with a high traffic volume. In the United States, several big eastern railroads used them, primarily the New York Central and Pennsylvania Railroad
Pennsylvania Railroad
The Pennsylvania Railroad was an American Class I railroad, founded in 1846. Commonly referred to as the "Pennsy", the PRR was headquartered in Philadelphia, Pennsylvania....
.
In Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
, they could be found on all main lines, except on the Southern Railway.
Use by diesel locomotives
Diesel locomotiveDiesel locomotive
A diesel locomotive is a type of railroad locomotive in which the prime mover is a diesel engine, a reciprocating engine operating on the Diesel cycle as invented by Dr. Rudolf Diesel...
s were introduced in the United Kingdom by British Railways in the 1950s, working alongside steam traction until 1968. Passenger vehicles were heated by steam from the locomotive boiler at that time, and the early diesel locomotives were provided with auxiliary boilers to provide the steam. Locomotives intended for long non-stop runs (such as the Class 40
British Rail Class 40
The British Rail Class 40 is a type of British railway diesel locomotive. Built by English Electric between 1958 and 1962, and eventually numbering 200, they were for a time the pride of the British Rail early diesel fleet...
and Class 55
British Rail Class 55
The British Rail Class 55 is a class of diesel locomotive built in 1961 and 1962 by English Electric. They were designed for the high-speed express passenger services on the East Coast Main Line between and Edinburgh. They gained the name "Deltic" from the prototype locomotive, DP1 Deltic, which...
) were fitted with water scoops to allow them to replenish the steam generator's water supply from troughs/pans. The withdrawal of steam traction and the introduction of rolling stock with electric rather than steam heating removed the need for such equipment on later types and scoop-equipped locomotives had their scoops removed.
Locations
A map showing the location of GWR troughs in the 1930s is reproduced in the book 'The Great Western Railway'. They are typically at spacings of 40 to 50 miles, but with some wide variations, and a few instances of trough locations very close to major stopping points (e.g. St Annes Park, two miles from Bristol Temple Meads). The lengths are also given: they vary from 524 to 620 yards (480 to 570 metres).The practice of drafting water in this way gave rise to the American expression, "Jerkwater Town," used generally to indicate a small town or out-of-the-way place. If a town were sizable, it would have a water tank for which the train would stop to take on water. If the town didn't rate a water tank, it would be forced to "jerk" water while moving to refill the engine's tender.
Alternative techniques
The Norfolk & Western Railroad in America came up with a novel way of not using track pans. They found certain grades were "momentum" grades. If the train stopped to take on water, the train had to have a helper engine to make it up the corresponding grade. If the train did not have to stop for water, then the "momentum" of the train would help it make the corresponding grade. Norfolk & Western added auxiliary water tenders, cars that only contained water. By carrying extra water the train did not have to stop for water, and did not need a helper. Norfolk & Western eliminated several helper districts as a result of using auxiliary water tenders.External links
- http://www.youtube.com/watch?v=aQPdRS-9p_I Vintage cine of British steam engines in the 1950s using water troughs/track pans