![Railroad torpedo](https://upload.wikimedia.org/wikipedia/commons/0/0f/Railroad_torpedo.jpg)
A railway detonator (torpedo in North America) is a coin-sized device that is used as a loud warning signal to
train drivers
A train driver, engine driver, engineman or locomotive driver, commonly known as an engineer or railroad engineer in the United States and Canada, and also as a locomotive handler, locomotive operator, train operator, or motorman, is a pers ...
. It is placed on the top of the
rail
Rail or rails may refer to:
Rail transport
*Rail transport and related matters
*Rail (rail transport) or railway lines, the running surface of a railway
Arts and media Film
* ''Rails'' (film), a 1929 Italian film by Mario Camerini
* ''Rail'' ( ...
, usually secured with two lead straps, one on each side. When the wheel of the train passes over, it explodes, emitting a loud bang. It was invented in 1841 by English inventor
Edward Alfred Cowper
Edward Alfred Cowper (10 December 1819 London – 9 May 1893 Rastricke, Weybridge, Surrey) was a British mechanical engineer.
Biography
He was born on 10 December 1819 in London to professor Edward Shickle Cowper (1790–1852), head of the depa ...
.
Uses
![Track Detonator](https://upload.wikimedia.org/wikipedia/commons/c/ca/Track_Detonator.JPG)
Typical uses of detonators include:
* A warning, caution or stop signal in dense fog, when
signals
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...
are difficult to see
* A warning of a train stopped on the line ahead by an incident or accident—the train crew are usually responsible for placing the detonators
* A warning of ongoing engineering works ahead
* When a
signaller
A signaller, signalman, colloquially referred to as a radioman or signaleer in the armed forces is a specialist soldier, sailor or airman responsible for military communications. Signallers, a.k.a. Combat Signallers or signalmen or women, are ...
or other railway employee requires to stop approaching trains in an emergency
On a high-speed line, detonators may need to be placed on both rails.
As with all
explosives
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An expl ...
, detonators can become unstable over time and must, therefore, be replaced regularly.
They are triggered by pressure, rather than impact. This makes them safe during transport, as they normally cannot detonate in a bag or storage container.
In the United States
Upon hearing the noise of a torpedo exploding, the
engineer
Engineers, as practitioners of engineering, are professionals who invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considering the l ...
reduces speed to 20 mph or less, not resuming its original speed until at least two miles beyond where it encountered the device. They were traditionally used in pairs to ensure that the sound registered with train crews. Torpedoes are essentially obsolete in the U.S. as soundproof construction of modern locomotive cabs renders them useless.
Quoting from the terminology book of the
Brotherhood of Railroad Signalmen
The Brotherhood of Railroad Signalmen (BRS) is a labor union in the United States. It represents workers who install, maintain, and repair railroad traffic control systems. These include switching, signaling, and highway-rail crossing warning sy ...
:
A torpedo is a device which is strapped to the top of a rail. When a train drives over the torpedo, it emits a very loud "bang" which can be heard over the noise of the engine, and signals the engineer to stop immediately. Torpedoes are generally placed by the flagman when protecting a train ahead.
Torpedoes are about 2" × 2", red in color, about 3/4" high, and have two lead straps attached, which hold it to the rail. The torpedo has discs inside and are filled with detonating powder. The torpedo was invented about 1874.
In the United Kingdom
If a train unexpectedly explodes a detonator, the driver is required to stop immediately and investigate.
Detonators are usually deployed in groups of three, spaced 20 metres apart. When being used on electrified lines detonators must be placed on the rail which is furthest from the
conductor rail (aka 'third rail'). If a train is about to explode a detonator, personnel are required to stand at least 30 metres away from it and turn away.
There are three types of detonator protection in the UK:
* Emergency Protection:
![Olbramovice, rekonstrukce trati, kolejové stroje](https://upload.wikimedia.org/wikipedia/commons/b/be/Olbramovice%2C_rekonstrukce_trati%2C_kolejov%C3%A9_stroje.jpg)
If a train is involved in an accident or fails ''and it is not possible to contact the signaller,'' then emergency protection must be used. Track circuit operating clips (TCOC) must be placed on all affected lines, and three detonators must be placed at a distance of 2 kilometres in the direction from which a train is most likely to approach.
* Assistance Protection: If a train fails and communication can be made with the signaller, then assistance protection must be used. The driver of the failed train must place three detonators at a distance of 300 metres from the failed train in the direction from which the assisting train will approach (unless there is a stop signal within 300 metres of the rear of the failed train). The driver will remain at this ''assistance protection point'' with a red flag (or lamp in darkness) and await the assisting train.
* Possession Protection: Possessions (worksites) on the railway are operated separately from the running lines and train movements inside them are not controlled by the signaller. Instead a PICOP (person in charge of possession) controls movement into and out of the possession in co-ordination with the signaller, and an Engineering Manager is responsible for movements of rail vehicles within the possession. Three detonators and a Stop Board are positioned at the entry and exit to the possession to prevent any unauthorised trains from entering accidentally, and also to clearly define the extent of the possession.
In Germany
Detonators were used where hazards had to be secured and there was no time for other signaling or if there was a danger that another signal might not be recognizable in time, for example due to fog or snow. To give the emergency signal, three detonators were placed in short succession, with the explosion of a single detonator being a stop signal. Since 1986 detonators have no longer been used on German railways. Only the
ICE 3
ICE 3, or Intercity-Express 3, is a family of high-speed electric multiple unit trains operated by Deutsche Bahn. It includes classes 403, 406, 407 and 408, which are known as ICE 3, ICE 3M, New ICE 3 and ICE 3neo respectively. Three multisystem ...
trains that travel to France still have detonators on board because of French regulations.
In Taiwan
The use of detonators has been superseded by radio communications since the early 1950s. In November 2010, the
Taiwan Railway Administration
Taiwan Railways Administration (TRA) is a railway operator in Taiwan. It is an agency of the Ministry of Transportation and Communications, responsible for managing, maintaining, and running conventional passenger and freight railway services ...
deployed 800 detonators for destruction on maintenance tracks. It received media attention, emitting sounds similar to the culturally significant
firecracker
A firecracker (cracker, noise maker, banger) is a small explosive device primarily designed to produce a large amount of noise, especially in the form of a loud bang, usually for celebration or entertainment; any visual effect is incidental t ...
s.
In Australia
Today known as audible track warning signals,
or audible track warning devices, detonators are used to attract the attention of train crews when track repairs or an obstruction are ahead, or when a hand signaller is acting for a signal.
In Tanzania
Detonators are used to attract the attention of train crews in case of:
* Visibility of fixed signal restricted by fog, mist or other circumstance
* obstruction of line, whether by train or otherwise
* protection of push trolleys
* protection of shunting movement outside the station limits during total failure of communication
Detonator placer
Many mechanical
signal box
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...
es in the
UK were equipped with detonator placers that placed detonators on a running line when a
lever
A lever is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or ''fulcrum''. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load and effort, the lever is div ...
was operated. The levers were painted a striking white and black
chevron
Chevron (often relating to V-shaped patterns) may refer to:
Science and technology
* Chevron (aerospace), sawtooth patterns on some jet engines
* Chevron (anatomy), a bone
* '' Eulithis testata'', a moth
* Chevron (geology), a fold in rock ...
pattern, pointing upwards for the "up" line, downwards for the "down" line. In some cases, the placers were fed from a cartridge holding a number of detonators.
Composition
According to ''Military and Civilian Pyrotechnics'' by Ellern, page 376, FORMULA 155 – Railroad Torpedo, is by mass:
*
Potassium chlorate
Potassium chlorate is a compound containing potassium, chlorine and oxygen, with the molecular formula KClO3. In its pure form, it is a white crystalline substance. After sodium chlorate, it is the second most common chlorate in industrial use. It ...
– 40%
*
Sulfur
Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...
– 16%
* Sand (—60
mesh
A mesh is a barrier made of connected strands of metal, fiber, or other flexible or ductile materials. A mesh is similar to a web or a net in that it has many attached or woven strands.
Types
* A plastic mesh may be extruded, oriented, ex ...
) – 37%
* Binder – 5%
* Neutralizer – 2%
Garratt locomotives
The length of
Garratt
A Garratt (often referred to as a Beyer Garratt) is a type of steam locomotive invented by British engineer Herbert William Garratt that is articulated into three parts. Its boiler, firebox, and cab are mounted on a centre frame or "bridge ...
locomotives made the sound of a detonator hard to hear, so
New South Wales 60 class locomotive
The AD60 class were Beyer-Garratt patent articulated four-cylinder, simple, non-condensing, coal-fired superheated, 4-8-4+4-8-4 heavy goods steam locomotives built by Beyer, Peacock and Company for the New South Wales Government Railways in Aust ...
had "sound pipes" to bring the noise of the explosion to the crew.
References
External links
*
* {{cite web , last1=Clayton Penistone Group , title=Safety Data Sheet - Railway Fog Signal , url=http://www.clayton-penistone.co.uk/SharedFiles/Download.aspx?pageid=25&mid=60&fileid=1430 , accessdate=16 July 2019 , archiveurl=https://web.archive.org/web/20161121231428/http://www.clayton-penistone.co.uk/SharedFiles/Download.aspx?pageid=25&mid=60&fileid=1430 , archivedate=21 November 2016 , language=English , format=English , date=25 April 2016
Explosives
Railway safety