1.
Train station
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A train station, railway station, railroad station, or depot is a railway facility where trains regularly stop to load or unload passengers or freight. It generally consists of at least one platform and a station building providing such ancillary services as ticket sales. If a station is on a line, it often has a passing loop to facilitate traffic movements. The smallest stations are most often referred to as stops or, in parts of the world. Stations may be at level, underground, or elevated. Connections may be available to intersecting rail lines or other modes such as buses. In British usage, the station is commonly understood to mean a railway station unless otherwise qualified. In the United States, the most common term in contemporary usage is train station, Railway station and railroad station are less frequent. Outside North America, a depot is place where buses, trains, or other vehicles are housed and maintained and from which they are dispatched for service. The two-storey Mount Clare station in Baltimore, Maryland, which survives as a museum, first saw service as the terminus of the horse-drawn Baltimore. The oldest terminal station in the world was Crown Street railway station in Liverpool, built in 1830, as the first train on the Liverpool-Manchester line left Liverpool, the station is slightly older than the Manchester terminal at Liverpool Road. The station was the first to incorporate a train shed, the station was demolished in 1836 as the Liverpool terminal station moved to Lime Street railway station. Crown Street station was converted to a goods station terminal, the first stations had little in the way of buildings or amenities. The first stations in the modern sense were on the Liverpool and Manchester Railway, manchesters Liverpool Road Station, the second oldest terminal station in the world, is preserved as part of the Museum of Science and Industry in Manchester. It resembles a row of Georgian houses, dual-purpose stations can sometimes still be found today, though in many cases goods facilities are restricted to major stations. In rural and remote communities across Canada and the United States, such stations were known as flag stops or flag stations. Many stations date from the 19th century and reflect the architecture of the time. Countries where railways arrived later may still have such architecture, as later stations often imitated 19th-century styles, various forms of architecture have been used in the construction of stations, from those boasting grand, intricate, Baroque- or Gothic-style edifices, to plainer utilitarian or modernist styles
2.
Railway signalling
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Railway signalling is a system used to direct railway traffic and keep trains clear of each other at all times. Trains move on fixed rails, making them susceptible to collision. This susceptibility is exacerbated by the weight and inertia of a train. Most forms of control involve movement authority being passed from those responsible for each section of a rail network to the train crew. The set of rules and the equipment used to accomplish this determine what is known as the method of working. Not all these methods require the use of signals. The earliest rail cars were first hauled by horses or mules, a mounted flagman on a horse preceded some early trains. Hand and arm signals were used to direct the “train drivers”, foggy and poor-visibility conditions gave rise to flags and lanterns. Wayside signalling dates back as far as 1832, and used elevated flags or balls that could be seen from afar, the simplest form of operation, at least in terms of equipment, is to run the system according to a timetable. Every train crew understands and adheres to a fixed schedule, trains may only run on each track section at a scheduled time, during which they have possession and no other train may use the same section. When trains run in opposite directions on a railroad, meeting points are scheduled. Neither train is permitted to move before the other has arrived, in the US the display of two green flags is an indication that another train is following the first and the waiting train must wait for the next train to pass. In addition, the carrying the flags gives eight blasts on the whistle as it approaches. The waiting train must return eight blasts before the flag carrying train may proceed, the timetable system has several disadvantages. First, there is no confirmation that the track ahead is clear. A second problem is the systems inflexibility, trains cannot be added, delayed, or rescheduled without advance notice. A third problem is a corollary of the second, the system is inefficient, to provide flexibility, the timetable must give trains a broad allocation of time to allow for delays, so the line is not in the possession of each train for longer than is otherwise necessary. Nonetheless, this system permits operation on a vast scale, with no requirements for any kind of communication that travels faster than a train, timetable operation was the normal mode of operation in North America in the early days of the railroad
3.
Train
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A train is a form of rail transport consisting of a series of vehicles that usually runs along a rail track to transport cargo or passengers. Motive power is provided by a locomotive or individual motors in self-propelled multiple units. Although historically steam propulsion dominated, the most common forms are diesel and electric locomotives. Other energy sources include horses, engine or water-driven rope or wire winch, gravity, pneumatics, batteries, the word train comes from the Old French trahiner, from the Latin trahere pull, draw. There are various types of trains that are designed for particular purposes, a train may consist of a combination of one or more locomotives and attached railroad cars, or a self-propelled multiple unit. The first trains were rope-hauled, gravity powered or pulled by horses, from the early 19th century almost all were powered by steam locomotives. A passenger train is one which includes passenger-carrying vehicles which can often be very long, one notable and growing long-distance train category is high-speed rail. In order to much faster operation over 500 km/h, innovative Maglev technology has been researched for years. In most countries, such as the United Kingdom, the distinction between a tramway and a railway is precise and defined in law, a freight train uses freight cars to transport goods or materials. Freight and passengers may be carried in the train in a mixed consist. Rail cars and machinery used for maintenance and repair of tracks, etc. are termed maintenance of way equipment, similarly, dedicated trains may be used to provide support services to stations along a train line, such as garbage or revenue collection. There are various types of trains that are designed for particular purposes, a train can consist of a combination of one or more locomotives and attached railroad cars, or a self-propelled multiple unit. Trains can also be hauled by horses, pulled by a cable, special kinds of trains running on corresponding special railways are atmospheric railways, monorails, high-speed railways, maglev, rubber-tired underground, funicular and cog railways. A passenger train may consist of one or several locomotives and coaches, alternatively, a train may consist entirely of passenger carrying coaches, some or all of which are powered as a multiple unit. In many parts of the world, particularly the Far East and Europe, freight trains are composed of wagons or trucks rather than carriages, though some parcel and mail trains are outwardly more like passenger trains. Trains can also be mixed, comprising both passenger accommodation and freight vehicles, special trains are also used for track maintenance, in some places, this is called maintenance of way. A train with a locomotive attached at each end is described as top and tailed, where a second locomotive is attached temporarily to assist a train up steep banks or grades it is referred to as banking in the UK, or helper service in North America. Recently, many loaded trains in the United States have been made up one or more locomotives in the middle or at the rear of the train
4.
Siemens Nexas
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The Siemens Nexas are a class of electric multiple units manufactured by Siemens Transportation Systems for the suburban railway network of Melbourne, Australia between 2002 and 2005. The design of the trains was based on the Siemens Modular Metro, in March 2000 M>Train ordered 62 Siemens Nexas trains to fulfill a franchise commitment to replace its fleet of Hitachi trains. The original order was for 62 3-car sets, with an option for an additional ten 3-car sets. In December 2002 just before the first was delivered, National Express handed the M>Train franchise back to the Government of Victoria, all passed to Connex Melbourne in April 2004. The option for ten additional trains was exercised in August 2005, Siemens Rail Services was contracted to provide maintenance of the trains for a period of 15 years at Newport Workshops. With the refranchising of the network to Metro Trains Melbourne in 2009, the first entered service on 21 March 2003 with the last delivered in January 2006. In December 2014, Siemens Nexas 831M-2566T -832M with a seating layout added extra hand rails layout at the doors. In late 2006 the trains suffered a number of braking discrepancies while in service,14 trains overshot platforms in the space of three days, the 15 units involved in these overshoots were withdrawn from service for checks, and instructions were issued to the drivers to minimise further occurrences. By mid-January 2007, a total of 24 three-carriage trains had been impounded for testing after 20 further incidents of over-running stations since 22 December 2006. On 13 January 2007, Connex stopped running the Siemens Nexas trains as 3-car sets until the issue was resolved. On 29 January 2007, Connex cancelled 37 peak-period services until further notice, by 1 February 2007,38 three-car sets were withdrawn due to continuing braking failures, meaning that almost half of the Siemens Nexas fleet was out of revenue service. The entire fleet has now re-entered service, although with a not to run single unit operations. In December 2008 train operator Connex commenced proceedings in the Supreme Court to claim damages from Siemens, Connex claims Siemens provided trains with a braking system that was defective, faulty and inadequate, the trains being not fit for their purpose and were not of merchantable quality. In March 2009, it was reported that three Siemens Nexas trains had been impounded due to new braking incidents in the week prior, the sand boxes are fitted to the middle two bogies of each 3-car set. In June 2011 installation of sanding equipment was completed across the entire fleet, speed restrictions have now been lifted on all Siemens Nexas trains. All were built by Siemens Transportation Systems, Vienna with the final fitout completed at Newport Workshops, there are several notable differences between the Siemens Nexas trains and other trains which operate in Melbourne. Two doors per carriage per side, plug-type doors - hinged outward and slide along the outside of the vehicle when opening. Passengers can freely move from carriage to carriage, within a 3-carriage set, without opening doors, the Siemens Nexas are fitted with Passenger information system produced by the German firm Annax
5.
Electric motor
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An electric motor is an electrical machine that converts electrical energy into mechanical energy. The reverse of this is the conversion of energy into electrical energy and is done by an electric generator. In normal motoring mode, most electric motors operate through the interaction between an electric motors magnetic field and winding currents to generate force within the motor, small motors may be found in electric watches. General-purpose motors with highly standardized dimensions and characteristics provide convenient mechanical power for industrial use, the largest of electric motors are used for ship propulsion, pipeline compression and pumped-storage applications with ratings reaching 100 megawatts. Electric motors may be classified by electric power source type, internal construction, application, type of motion output, perhaps the first electric motors were simple electrostatic devices created by the Scottish monk Andrew Gordon in the 1740s. The theoretical principle behind production of force by the interactions of an electric current. The conversion of energy into mechanical energy by electromagnetic means was demonstrated by the British scientist Michael Faraday in 1821. A free-hanging wire was dipped into a pool of mercury, on which a permanent magnet was placed, when a current was passed through the wire, the wire rotated around the magnet, showing that the current gave rise to a close circular magnetic field around the wire. This motor is often demonstrated in experiments, brine substituting for toxic mercury. Though Barlows wheel was a refinement to this Faraday demonstration. In 1827, Hungarian physicist Ányos Jedlik started experimenting with electromagnetic coils, after Jedlik solved the technical problems of the continuous rotation with the invention of the commutator, he called his early devices electromagnetic self-rotors. Although they were used only for instructional purposes, in 1828 Jedlik demonstrated the first device to contain the three components of practical DC motors, the stator, rotor and commutator. The device employed no permanent magnets, as the fields of both the stationary and revolving components were produced solely by the currents flowing through their windings. His motor set a record which was improved only four years later in September 1838 by Jacobi himself. His second motor was powerful enough to drive a boat with 14 people across a wide river and it was not until 1839/40 that other developers worldwide managed to build motors of similar and later also of higher performance. The first commutator DC electric motor capable of turning machinery was invented by the British scientist William Sturgeon in 1832, following Sturgeons work, a commutator-type direct-current electric motor made with the intention of commercial use was built by the American inventor Thomas Davenport, which he patented in 1837. The motors ran at up to 600 revolutions per minute, and powered machine tools, due to the high cost of primary battery power, the motors were commercially unsuccessful and Davenport went bankrupt. Several inventors followed Sturgeon in the development of DC motors but all encountered the same battery power cost issues, no electricity distribution had been developed at the time
6.
Valve
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A valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically fittings, but are discussed as a separate category. In an open valve, fluid flows in a direction from higher pressure to lower pressure, the word is derived from the Latin valva, the moving part of a door, in turn from volvere, to turn, roll. The simplest, and very ancient, valve is simply a freely hinged flap which drops to obstruct fluid flow in one direction and this is called a check valve, as it prevents or checks the flow in one direction. Modern control valves may regulate pressure or flow downstream and operate on sophisticated automation systems, even aerosols have a tiny valve built in. Valves are also used in the military and transport sectors, valves may be operated manually, either by a handle, lever, pedal or wheel. Valves may also be automatic, driven by changes in pressure, temperature and these changes may act upon a diaphragm or a piston which in turn activates the valve, examples of this type of valve found commonly are safety valves fitted to hot water systems or boilers. More complex control systems using valves requiring automatic control based on an external input require an actuator, an actuator will stroke the valve depending on its input and set-up, allowing the valve to be positioned accurately, and allowing control over a variety of requirements. Valves vary widely in form and application, sizes typically range from 0.1 mm to 60 cm. Special valves can have a diameter exceeding 5 meters, valve costs range from simple inexpensive disposable valves to specialized valves which cost thousands of US dollars per inch of the diameter of the valve. Disposable valves may be found in household items including mini-pump dispensers. Valves are quite diverse and may be classified into a number of basic types, valves may also be classified by how they are actuated, Hydraulic Pneumatic Manual Solenoid valve Motor The main parts of the most usual type of valve are the body and the bonnet. These two parts form the casing that holds the fluid going through the valve, the valves body is the outer casing of most or all of the valve that contains the internal parts or trim. The bonnet is the part of the encasing through which the stem passes, the bonnet typically screws into or is bolted to the valve body. Valve bodies are usually metallic or plastic, brass, bronze, gunmetal, cast iron, steel, alloy steels and stainless steels are very common. Seawater applications, like plants, often use duplex valves, as well as super duplex valves, due to their corrosion resistant properties. Alloy 20 valves are used in sulphuric acid plants, whilst monel valves are used in hydrofluoric acid plants. Hastelloy valves are used in high temperature applications, such as nuclear plants
7.
Railway brake
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Brakes are used on the cars of railway trains to enable deceleration, control acceleration or to keep them standing when parked. Clasp brakes are one type of historically used on trains. In the earliest days of railways, braking technology was primitive, some railways fitted a special deep-noted brake whistle to locomotives to indicate to the porters the necessity to apply the brakes. All the brakes at this stage of development were applied by operation of a screw and linkage to brake blocks applied to wheel treads, and it was also unreliable, as the application of brakes by guards depended upon them hearing and responding quickly to a whistle for brakes. This had become apparent from the trials on railway brakes carried out at Newark in the previous year, the chief types of solution were, The chain brake, such as the Heberlein brake, in which a chain was connected continuously along the train. As with car brakes, actuating pressure to apply brakes was transmitted hydraulically and these found some favor in the UK, but even in the UK problems were found with the water used as brake fluid freezing The Westinghouse air brake system. The Westinghouse system uses smaller air reservoirs and brake cylinders than the vacuum equipment. An ejector on the created a vacuum in a continuous pipe along the train. This system was very cheap and effective, but it had the weakness that it became inoperative if the train became divided or if the train pipe was ruptured. This system was similar to the vacuum system, except that the creation of vacuum in the train pipe exhausted vacuum reservoirs on every vehicle. If the driver applied the brake, his drivers brake valve admitted atmospheric air to the pipe. Being an automatic brake, this system applies braking effort if the train divided or if the train pipe is ruptured. Its disadvantage is that the vacuum reservoirs were required on every vehicle, and their bulk. Note, there are a number of variants and developments of all these systems, the Newark trials showed the braking performance of the Westinghouse air-brakes to be distinctly superior but for other reasons it was the vacuum system that was generally adopted on UK railways. Goods and mineral vehicles were provided with hand brakes by which the brakes could be applied by a lever operated by staff on the ground. Early goods vehicles had brake handles on one side only and random alignment of the vehicles gave the guard sufficient braking but, from about 1930 and these trains, not fitted with continuous brakes were described as unfitted trains and they survived in British practice until about 1985. By 1952 only 14% of open wagons, 55% of covered, in the early days of diesel locomotives, a purpose-built brake tender was attached to the locomotive to increase braking effort when hauling unfitted trains. The brake tender was low, so that the driver could see the line and signals ahead if the brake tender was propelled ahead of the locomotive
8.
Spring (device)
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A spring is an elastic object used to store mechanical energy. Springs are usually out of spring steel. There are a number of spring designs, in everyday usage the term often refers to coil springs. When a spring is compressed or stretched from its resting position, the rate or spring constant of a spring is the change in the force it exerts, divided by the change in deflection of the spring. That is, it is the gradient of the force versus deflection curve, an extension or compression springs rate is expressed in units of force divided by distance, for example lbf/in or N/m. A torsion spring is a spring that works by twisting, when it is twisted about its axis by an angle, a torsion springs rate is in units of torque divided by angle, such as N·m/rad or ft·lbf/degree. The inverse of spring rate is compliance, that is, if a spring has a rate of 10 N/mm, the stiffness of springs in parallel is additive, as is the compliance of springs in series. Springs are made from a variety of materials, the most common being spring steel. Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel, some non-ferrous metals are also used including phosphor bronze and titanium for parts requiring corrosion resistance and beryllium copper for springs carrying electrical current. Simple non-coiled springs were used throughout history, e. g. the bow. In the Bronze Age more sophisticated spring devices were used, as shown by the spread of tweezers in many cultures, coiled springs appeared early in the 15th century, in door locks. The first spring powered-clocks appeared in that century and evolved into the first large watches by the 16th century, in 1676 British physicist Robert Hooke discovered Hookes law which states that the force a spring exerts is proportional to its extension. Compression spring – is designed to operate with a compression load, flat spring – this type is made of a flat spring steel. Machined spring – this type of spring is manufactured by machining bar stock with a lathe and/or milling operation rather than a coiling operation, since it is machined, the spring may incorporate features in addition to the elastic element. Machined springs can be made in the load cases of compression/extension, torsion. Serpentine spring - a zig-zag of thick wire - often used in modern upholstery/furniture, the most common types of spring are, Cantilever spring – a spring which is fixed only at one end. Coil spring or helical spring – a spring is of two types, Tension or extension springs are designed to become longer under load and their turns are normally touching in the unloaded position, and they have a hook, eye or some other means of attachment at each end. Compression springs are designed to become shorter when loaded and their turns are not touching in the unloaded position, and they need no attachment points
9.
Pulse code cab signaling
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Pulse code cab signaling is a form of cab signaling technology developed in the United States by the Union Switch and Signal corporation for the Pennsylvania Railroad in the 1920s. In its home territory on former PRR successor Conrail owned lines, in 1922 the Interstate Commerce Commission issued a ruling requiring trains to be equipped with automatic train stop technology to operate at 80 mph or greater. The task was assigned to Union Switch and Signal corporation, the PRRs preferred signal supplier, the first test installation between Sunbury and Lewistown, PA in 1923 used the tracks as an inductive loop coupled to the locomotive’s receiver. The system had two 60 Hz signals, the break-sensing “track” signal was fed down one rail towards the oncoming train and crossed through its wheels, returning in the other rail. The pickup just ahead of the wheels would sum the approaching current from one side with the current on the other. The externally returned ”loop” signal was fed into and out of the mid tap of a resistor across each end of the track circuit, the pickup would sum the approaching current on each side as it carried on past to the far end of the track. This signal was shifted 90 degrees from the other, the signals were applied one or both continuously to give Approach or Clear aspects while no signal was a Restricting aspect. The test installation eliminated wayside block signals, and trains relied solely on cab signals. The pivotal change was that now it would come on above Restricting merely as a carrier and 1.25 to 3 Hz on-off pulsing of it would be used as a code to convey the aspects. The presence of the carrier alone was not meaningful, no pulsing would still mean a Restricting aspect and this new system allowed four signal aspects, Restricting, Approach, Approach Medium, and Clear. Later, passenger engines were upgraded with speed control which enforced the rulebook speed associated with each cab signal, over time the PRR installed cab signals over much of its eastern system from Pittsburgh to Philadelphia, New York to Washington. This system was inherited by Conrail and Amtrak and various commuter agencies running on former PRR territory such as SEPTA. Because all trains running in cab signal territory had to be equipped with cab signals, pulse code cab signals work by sending metered pulses along an existing AC track circuit operating at some chosen carrier frequency. The pulses are detected via induction by a sensor hanging a few inches above the rail before the set of wheels. The codes are measured in pulses per minute and for the 4-aspect PRR system are set at 180 ppm for Clear,120 ppm for Approach Medium,75 ppm for Approach and 0 for Restricting. The pulse rates are chosen to avoid any one rate being a multiple of another leading to reflected harmonics causing false indications, the system is failsafe in that the lack of code would display a Restricting signal. The codes would be transmitted to the train from the limit in front of it. This way if the rail was broken or another train entered the block, any codes would not reach the onrushing train, Trains with an insufficient number of axles will not short out all of the cab signal current so that following trains might receive an incorrect aspect
10.
Railways in Melbourne
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The Melbourne rail network is operated by Metro Trains Melbourne under franchise from the Government of Victoria. A rapid transit system for Melbourne is currently in planning stages, Melbournes suburban railway network consists of 16 electrified lines, the central City Loop subway, and 207 stations, with a total length of 372 km of electrified lines. The suburban network operates between approximately 5,00 a. m. and midnight, the network is primarily at ground level, with more than 170 level crossings, and some tracks shared with freight trains and V/Line regional services. In the 2013–14 financial year, the Melbourne rail network recorded 232 million passenger trips, in 1839, the Government Surveyor Robert Hoddle, who laid out Melbournes road grid, provided for a railway linking Melbourne and Hobsons Bay. On 8 February 1853 the Government also approved the establishment of the Geelong and Melbourne Railway Company, work began in March 1853 on the Sandridge railway line, stretching 4 kilometres from the Melbourne terminus to Sandridge. The line was owned and operated by Melbourne and Hobsons Bay Railway Company, in 1855 the Government conducted enquiries and carried out surveys into country railways. On 1 April 1856, the Railway Department was established as part of the Board of Land, on 23 May of that year the Melbourne, Mount Alexander and Murray River Railway Company was taken over by the Government. Trains were ordered from Robert Stephenson and Company of the United Kingdom, the first train was locally built by Robertson, Martin & Smith, however, owing to delays in shipping. Australias first steam locomotive was built in ten weeks and cost £2,700, forming the first steam train to travel in Australia, it made its maiden trip on 12 September 1854. The opening of the line occurred during the period of the Victorian gold rush—a time when both Melbourne and Victoria undertook massive capital works, each with its own gala opening, the inaugural journey on the Sandridge line was no exception. According to the Argus newspapers report of the day, Long before the hour appointed. A great crowd assembled round the station at the Melbourne terminus, the trip took 10 minutes, none of the later stations along the line having been built yet. On arriving at Station Pier, it was hailed with gun-salutes by the warships HMS Electra, by March 1855, the four engines ordered from the UK were all in service, with trains running every half-hour. They were named Melbourne, Sandridge, Victoria, and Yarra, the network was extended with lines being built to the suburbs, reaching a peak by the 1900s. Electrification of the system commenced from 1919, with multiple unit operation commencing at the same time. Melbournes second railway line opened 13 May 1857, when the Melbourne and this line was later extended by the St Kilda and Brighton Railway Company, which opened a line from St Kilda to Brighton in 1857. Country lines were built in 1857, with the Geelong. In 1859 the Williamstown railway line opened, connecting Williamstown and Geelong to Spencer Street Station and this line was extended to Windsor in 1860, connecting with the St Kilda and Brighton Railway Company line from St Kilda
11.
Union Switch & Signal
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Union Switch and Signal is a supplier of railway signaling equipment, systems and services in Pittsburgh, Pennsylvania. As of January 1,2009, US&S is known as Ansaldo STS USA, george Westinghouse founded Union Switch & Signal in 1881, consolidating the assets of the Union Electric Signal Company and the Interlocking Switch & Signal Company. In 1925 US&S acquired the Hall Signal Company, primarily to obtain the latter companys patents for searchlight signals, US&S operated as an independent company until 1917, when it became a subsidiary of the Westinghouse Air Brake Company. In 1968, American Standard purchased WABCO and reorganized US&S as a separate division, in 1988, Ansaldo purchased US&S from American Standard. In November 1993, US&S became a traded company with shares listed on Nasdaq. In December 1996, US&S merged with the other signaling investments of Ansaldo, as a result of that merger, US&S is now a wholly owned subsidiary of Ansaldo STS, a global supplier of signaling, control and automation systems. The company was renamed Ansaldo STS – USA in January 2009, throughout its history, US&S had manufacturing facilities in the borough of Swissvale, Pennsylvania, near Pittsburgh. The Swissvale plant was closed in 1985 and demolished in 1986, US&S moved manufacturing operations to a facility in Batesburg-Leesville, South Carolina. It maintained a facility in Pittsburgh. Other facilities include a service and repair shop in Kingston, Ontario, US&S built the first power interlocking system in the United States, a pneumatic design, in 1882 at East St. Louis, Illinois. Within several years the company developed a system, which was widely adopted by railroads across the country. In 1901 US&S developed the first electro-pneumatic automatic train stop system for the Boston Elevated Railway and this system was later adopted by the New York City Subway and other transit systems. In 1908 the company introduced a highway crossing gate. In 1923 US&S developed the first inductive train control system, the company developed coded track circuits, supporting bi-directional cab signalling, in 1934. The first digital rail yard control system was built by US&S in 1970, for the Atchison, Topeka & Santa Fe railway at Kansas City, US&S first patented the Model 15A Highway crossing bell on February 20,1917. The bell has been referred to as the Teardrop bell by railroaders and signal fans alike because of its unique shape. This bell has appeared on advertising literature for railroad signals as far back as the 1920s as far abroad as Chile and Italy on early wig wag crossings and this is the most commonly seen variation of the Teardrop. This bell is treasured by many for its slow low pitched ring at an irregular cadence, the production of this bell was discontinued sometime by the 1960s, but WABCO carried replacement castings and service manuals into the 1970s
