Brakes are used on rail cars to allow for slowdown, control acceleration (downhill) or keep them standing when parked. Although the basic principle is familiar from the use of vehicles on the highway, the operational features are more complex because of the need to control multiple connected cars and become effective on vehicles left without a major mover. The Handheld Brake is one of the types of brakes that historically used in trains.
Video Railway brake
Hari-hari awal
In the early days of the railways, braking technology was primitive. The first train has an operative on locomotive and vehicle tenders on the train, where "porter" or, in the United States brakemen, travels for purpose on brake-operated vehicles. Some railways have a very special brake whistle to the locomotive to show the porter the need to install the brakes. All brakes at this stage of development are applied by screw operations and the connection to the brake blocks is applied to the tread of the wheel, and these brakes can be used when the vehicle is parked. In the early days, the porters were traveling in crude oil shelters outside the vehicle, but the "guard assistants" who were traveling in passenger vehicles, and who had access to the brake wheels at their post, replaced them. Braking efforts that can be achieved are limited and also unreliable, because the application of brakes by guards depends on their hearing and responds quickly to the whistle for brakes.
The braking effort achieved is limited, and the initial development is the application of the steam brakes to the locomotive, where boiler pressure can be applied to the brake blocks on locomotive wheels. As train speed increases, it becomes important to provide a more robust braking system that can be used instantaneously and removed by railroad drivers, which are described as continuous brakes as this will be continuously effective throughout the train.
In Britain, the Abbots Ripton rail crash in January 1876 was exacerbated by the long-term stop of the long express train without brakes, which became clear - in bad conditions it could be far more than assumed when signal positioning. This has become clear from trials on the train brakes conducted in Newark the previous year, to help the Royal Commission then consider a train accident. In the words of a contemporary railroad official, this
shows that under normal conditions it takes a distance of 800 to 1200 meters to bring the train to rest while traveling at 45 ½ to 48 ½ mph, this is well below the usual travel speed of the fastest express train. The railway officials are not ready for this result and the need for more direct brake power is recognized
The trials were conducted after Abbots Ripton reported the following (for express trains roughly matched with one of those involved, as at 1 in 200 falls, but not as it braked under favorable conditions)
However, there is no clear technical solution to this problem, because of the need to achieve a uniform braking rate across trains, and because of the need to add and remove vehicles from trains at frequent points on the way. (On this date, train units are rare).
The main types of solutions are: Spring system: James Newall, wagon maker to Lancashire and Yorkshire Railway, in 1853 acquired a patent for a system in which the rods rotated past the length of the train used for rotating the brake lever in each carriage against the power of the cone spring brought in the cylinder. The rod, mounted on the roof of the carriage in the rubber journal, is equipped with a universal connection and short sliding parts to allow buffer compression. The brakes are controlled from one end of the train. The guard raised the stick, pressed the spring, to release the brakes; they are deflected by one ratchet under his control. When the ratchet is removed, the springs hit the brakes. If the train is divided, the brakes are not restrained by the ratchet in the guard compartment and the spring in each carriage forces the brakes to the wheels. Excess play in the clutch limits the effectiveness of the device to about five carriages; additional guards and brake compartments are required if this number is exceeded. The apparatus is sold to several companies and the system receives a recommendation from the Trade Council. L & amp; Y conducted a simultaneous test with a similar system designed by another employee, Charles Fay, but little difference was found in its effectiveness. In the Fay version, patented in 1856, the stem passes underneath the hopper and spring application, which offers an important "automatic" feature of Newall but can act too hard, replaced by worms and shelves for each brake.
Note: there are a number of variants and development of all these systems.
The Newark experiment shows the braking performance of the Westinghouse air-brakes to be very superior: but for other reasons it is a vacuum system that is generally adopted on British trains.
Next English practice
In English practice, only passenger trains are equipped with brakes continuously until about 1930; freight trains and minerals ran at slower speeds and relied on the brake power of locomotives and tender and brake vans - heavy vehicles provided at the rear of the train and occupied by guards.
Vehicles and minerals are provided with hand brakes that can be used for brakes by hand levers operated by staff in the field. This hand brake is used when needed when the vehicle is parked, but also when the train is required to descend the steep slope; The train then stops before it goes down and the guard goes forward to clamp the brake handle sufficiently to provide an adequate braking effort. The initial freight vehicle has a brake handle on one side only and the random alignment of the vehicle provides enough braking guards but, from about 1930, so-called "both sides" brakes are provided. These trains, which were not fitted with brakes constantly, were described as "unskilled" trains and they persisted in English practice until about 1985. However, from about 1930, semi-installed trains were introduced, where some freight vehicles were equipped with continuous braking and the proportion of such vehicles arranged alongside the locomotives provide sufficient braking power to run at a somewhat higher speed than the train that is not running. An experiment in January 1952 saw a 52-wagon, 850 ton, coal train running 127 miles (204 km) with an average of 38 miles per hour (61 km/h), compared to the usual train speed on the Midland main line of 15 miles per hour (24 km/h), or 20 miles per hour (32 km/h) to 25 miles per hour (40 km/h) of "installed" freights. In 1952 only 14% of open carriages, 55% closed and 80% of livestock trucks have vacuum brakes.
In the early days of diesel locomotives, brake tenders were made with the intention of being fitted to the locomotive to improve the braking effort when transporting an unworked train. The brake tender is low, so the driver can still see the line and signal forward if the brake tender is pushed (pushed) in front of the locomotive, which often happens.
In 1878 there were over 105 patents in various countries for the braking system, most of which were clearly stillborn.
Maps Railway brake
Ongoing brake
As train loads, gradients and speeds increase, braking becomes a problem. At the end of the 19th century, significantly better continuous brakes began to emerge. The earliest type of continuous brake is the chain brake, which runs the length of the carriage, to operate the brakes on all vehicles simultaneously.
The chain brake is immediately replaced by an air operated or operated brake. This brake uses a hose that connects all trains from the train, so the driver can apply or release the brakes with one valve in the locomotive.
This continuous brake can be simple or automatic, the fundamental difference is what happens if the train breaks into two. With a simple brake, pressure is required to brake, and all braking power is lost if the continuous hose is damaged for any reason. The simple non-automated brakes are thus useless when things go wrong, as demonstrated by the Armagh train disaster.
The automatic brake on the other hand uses air or vacuum pressure to hold the brake against the reservoir carried on each vehicle, which applies the brakes if the pressure/vacuum is lost inside the train pipe. The auto brakes are mostly "unsuccessful", even if the wrong tap faucet cover can cause an accident like an accident at the Gare de Lyon.
The standard Westinghouse Air brake has an additional enhancement of the triple valve, and local reservoirs on each wagon allow the brakes to be fully applied with only a slight drop in air pressure, reducing the time required to release the brakes as not all pressures are canceled into the atmosphere.
Non-automatic brakes still have roles on the engine and some of the first carriages, as they can be used to control the entire train without having to apply an automatic brake.
Type
Air brake versus vacuum
At the beginning of the 20th century, many British trains used vacuum brakes rather than air brakes used in most parts of the world. The main advantage of the vacuum is that the vacuum can be made by steam ejector without moving parts (and which can be supported by steam locomotive steam), whereas the air brake system requires a noisy and complicated compressor.
However, air brakes can be made much more effective than a vacuum brake for a given brake cylinder size. Air brake compressors are usually capable of producing a pressure of 90 psi (620 kPa) vs. only 15 psi (100 kPa) for vacuum. With a vacuum system, the maximum pressure difference is atmospheric pressure (14.7 psi or 101 kPa at sea level, less in altitude). Therefore, an air brake system can use a much smaller brake cylinder than a vacuum system to produce the same braking force. The advantages of this air brake increase at high altitudes, eg. Peru and Switzerland where the current vacuum brake is used by the secondary railway. The higher effectiveness of air brakes and the death of steam locomotives has seen air brakes become ubiquitous; However, vacuum braking is still used in India, in Argentina and in South Africa, but this will decline in the near future.
Air brake refinement
One of the increase of automatic air brake is to have a second air hose (main reservoir or main line) along the train to refill the air reservoir in each cart. This air pressure can also be used to operate the loading and unloading of doors on wheat carts and coal and ballast trains. On passenger coaches, the main reservoir pipe is also used to supply air to operate the door and air suspension.
Electroponic Brake
Higher-performing EP brakes use a "primary container" that drains air into all brake reservoirs on the train, with electrically controlled brake valves with a three-wire control circuit. It provides between four to seven levels of braking, depending on the train class. It is also possible for faster brake applications, since electrical control signals are effectively deployed directly to all vehicles on the train, whereas changes in air pressure activating the brakes in a conventional system can take several seconds or tens of seconds to propagate completely to the rear of the carriage. But this system is not used on freight trains because of the cost.
The system adopted at British Railways from 1950 onwards is described on an electro-pneumatic brake system on the British railway train
Pneumatically controlled brakes
Electronically controlled pneumatic brakes (ECP) is a late-twentieth-century development to handle very long and heavy freight trains, and is the development of EP brakes with higher levels of control. In addition, information about the operation of the brakes on each cart is returned to the driver's control panel.
With ECP, the power lines and controls are mounted from the cart to the cart from the front of the train to the rear. The electrical control signals are effectively deployed instantaneously, as opposed to changes in air pressure that spread at a somewhat slow speed limited in practice by resistance to the airflow of pipework, so that the brakes on all wagons can be applied simultaneously, or even backward forwards rather than from front to back. This prevents the cart in the rear wagon "pushing" on the front, and results in fewer stopping spacing and less equipment wear.
There are two brands of ECP brakes available, one by New York Air Brake and the other by Wabtec. Both of these types can be interchangeable.
Identify
Air brakes work with high pressure, and air hose at the end of small diameter rolling stock. On the other hand, the vacuum brakes work with low pressure, and the hose at the end of the rolling stock has a larger diameter.
The air brake on the outer vehicle of the train is turned off using the faucet. The vacuum brake on the outer rail vehicle is sealed by the sparked plugs into place.
Reversibility
The brake relationship between carts can be simplified if carts always point in the same way. Exceptions will be made for locomotives that are often turned on turntables or triangles.
On the new Fortescue train opened in 2008, the carriages were operated in sets, although its direction changed on the balloon loop at the harbor. ECP connection is only on one side and not unidirectional.
Crash with brakes
Damaged or incorrect brakes may cause an oncoming train; in some cases this has caused a train accident:
- Lac-MÃÆ'Â © gantic derailment, Quebec (2013), the brakes are not set correctly on a crude unattended cruise rail, a tank car that drove down the slope and slipped due to excessive speed on the curves in the city center, spilling five million liters of oil and causing a fire that killed 47 people.
- Democratic Republic of Congo west of Kananga (2007) - 100 killed.
- Igandu trains disaster, Tanzania (2002) - flees back - 281 dead.
- Tenga rail disaster, Mozambique (2002) - fleeing back - 192 dead.
- San Bernardino trains disaster, California (1989) - Brakes fail on freight trains that hit houses
- Gare de Lyon, France (1988) train accidents - valves closed due to errors that cause escape.
- Chester Common railway accident, England (1972) - brakes failed on fuel train that hit parked DMU
- Chapel-en-le-Frith, United Kingdom (1957) - The damaged steam pipe makes it impossible for the crew to install the brakes.
- Federal Express train accidents, Union stations, Washington, DC, (1953) - valves closed by poorly designed buffers.
- Torre del Bierzo, Spain (1944) disaster - the brakes failed on overloaded passenger trains that collided with others in a tunnel; the third train is unconscious and also bumps into it.
- Distractions of Saint-Michel-de-Maurienne, France 1917 - A train traveling at 3.3 percent, with airbrakes only 3 of 19 cars and in locomotives unable to keep trains below official speed - 700 killed.
- Armagh rail disaster, Northern Ireland (1889) - escapism caused a change in the law.
- The Shipton-on-Cherwell train accident, Oxford (1874) - was caused by a train wheel fracture.
Gallery
See also
Manufacturer
- Westinghouse Air Brake Company (WABCO), then Wabtec, USA
- Faiveley Transport, France
- Knorr-Bremse Railway System, Germany
- Westinghouse Brake and Signal Company Ltd. (now the Knorr-Bremse division), England
- New York Air Brake (now the Knorr-Bremse division), United States
- MZT HEPOS, Macedonia (now Wabtec division)
- Mitsubishi Electric, Japan
- Nabtesco, Japan
- Dellner, Sweden
- Aflink, South Africa
- Hanning & amp; Kahl GmbH LRT train, Hydraulic Brakes and control components, Germany
- Voith, Germany
- YUJIN Machinery Ltd, South Korea
References
Source
- British Transport Commission, London (1957: 142). Handbook for Steam Locomotive Train
Further reading
- Marsh, G.H. and Sharpe, A.C. Development of train brakes. Part 1 1730-1880 Railway engineering journal 2 (1) 1973, 46-53; Part 2 1880-1940 Railway engineering journal 2 (2) 1973, 32-42
- Victory, I.R. Continuous brake reception on trains in the UK Technology history 11 1986, 209-248. Includes developments from around 1850 to 1900.
External links
- RailTech
Source of the article : Wikipedia
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