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57-461: The TGV POS project was a unique extension of the TGV Duplex order. Alstom delivered to SNCF 38 new tri-current power cars and 19 sets of double-deck Duplex passenger carriages. The tri-current power cars were paired with the 19 sets of single-level passenger carriages from TGV Réseau trainsets, while the two-level Duplex passenger carriages were paired with the 38 dual-current power cars from

114-474: A double track railway is normally signalled in one direction only, with all signals facing the same direction on either line. Where bidirectional signalling is installed, signals face in both directions on both tracks (sometimes known as 'reversible working' where lines are not normally used for bidirectional working). Signals are generally not provided for controlling movements within sidings or yard areas. Signals have aspects and indications . The aspect

171-400: A traffic light . Hoods and shields are generally provided to shade the lights from sunlight which could cause false indications. Searchlight signals were the most often used signal type in the U.S. until recently. In these, a single incandescent light bulb is used in each head, and either an A.C. or D.C. relay mechanism is used to move a coloured spectacle (or "roundel") in front of

228-486: A "Stop" (or "Stop and Stay") indication, and permissive signals, which display a "Stop & Proceed" aspect. Furthermore, a permissive signal may be marked as a Grade Signal where a train does not need to physically stop for a "Stop & Proceed" signal, but only decelerate to a speed slow enough to stop short of any obstructions. Interlocking ('controlled') signals are typically absolute, while automatic signals (i.e. those controlled through track occupancy alone, not by

285-572: A bi-level arrangement, and later that year another TGV Sud-Est was modified to study the dynamic behavior of a train with a higher center of gravity. Discussions with GEC-Alstom began soon after, and in July 1990 the company won the contract to build the "TGV-2N", as it was then known. The contract was finalized in early 1991, at which point the official order was made. The first tests of a bi-level trainset were in November 1994. Soon after their first run,

342-406: A bracket which itself is mounted on a post. The left hand signal then controls the left-hand track, and the right signal the right-hand track. A gantry or signal bridge may also be used. This consists of a platform extending over the tracks; the signals are mounted on this platform over the tracks they control. In some situations or places, such as in tunnels, where there is insufficient room for

399-402: A green light on its own, which is high speed. A lamp proving relay would detect the reduction in current when more than two lamps are not working in a failed feather indicator, and prevent the green from showing. It can also display an indication on the signaller's panel. Due to this possibility, most signals are configured to be failsafe . For example, a flashing aspect can be used to display

456-430: A legal battle ending in damage payments for Eurotrain in 2004. Railway signal A railway signal is a visual display device that conveys instructions or provides warning of instructions regarding the driver's authority to proceed. The driver interprets the signal's indication and acts accordingly. Typically, a signal might inform the driver of the speed at which the train may safely proceed or it may instruct

513-533: A less restrictive signal. In this case, if the relay that controls the flashing fails, the signal becomes more restricting. A flashing yellow, in Canada and the United States, is part of an advance clear to stop indication, which means the second signal ahead is stop . A solid yellow means clear to stop , which means the next signal ahead is stop . Signals were originally controlled by levers situated at

570-425: A modern railroad may have different rules governing the interpretation of signal aspects. For example, stop aspect refers to any signal aspect that does not allow the driver to pass the signal. Signals control motion past the point at which the signal stands and into the next section of track. They may also convey information about the state of the next signal to be encountered. Signals are sometimes said to "protect"

627-492: A part of the signal being physically moved. The earliest types comprised a board that was either turned face-on and fully visible to the driver, or rotated away so as to be practically invisible. These signals had two or at most three positions. Semaphore signals were developed in France at the end of the 18th century, before being later adopted by the railways. The first railway semaphore was erected by Charles Hutton Gregory on

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684-531: A permissive signal has the lower set of lights offset (usually to the right) from the upper lights; in Victoria and New Zealand, an absolute signal displaying a red or white "A" light is also treated as a permissive signal. Some types of signal display separate permissive and absolute stop aspects. In Germany, the rules which apply to the respective signal are indicated by a vertical plate on the signal's post ( Mastschild ). Operating rules normally specify that

741-671: A pilot on the Staten Island Railway in New York City, at the time a B&O subsidiary; they were also applied to the Chicago and Alton Railroad when the latter was under B&O control, as well as on the B&;O itself. With the disappearance of the B&O into CSX they have been gradually replaced with NORAC color light signals. Lineside signals need to be mounted in proximity to the track which they control. When

798-408: A post or gantry, signals may be mounted at ground level. Such signals may be physically smaller (termed dwarf signals ). Rapid transit systems commonly use only dwarf signals due to restricted space. In many systems, dwarf signals are only used to display 'restrictive' aspects such as low speed or shunt aspects, and do not normally indicate 'running' aspects. Occasionally, a signal may be mounted to

855-409: A signal with an abnormality, such as one with an extinguished lamp or an entirely dark signal, must be interpreted as the most restrictive aspect – generally "Stop" or "Stop and Proceed". Signals differ both in the manner in which they display aspects and in the manner in which they are mounted with respect to the track. The oldest forms of signal displays their different indications by

912-477: A signalman) are usually permissive. Drivers need to be aware of which signals are automatic. In current British practice for example, automatic signals have a white rectangular plate with a black horizontal line across it. In US practice a permissive signal typically is indicated by the presence of a number plate. In the Australian states of New South Wales, Victoria and South Australia, as well as New Zealand,

969-409: A single deck Réseau set or another Duplex set. The Duplex feasibility study was completed in 1987. In 1988, a full-scale mockup was built to gauge customer reactions to the bi-level concept, traditionally associated with commuter and regional rail rather than with high-speed intercity trains. A TGV Sud-Est trailer was tested in revenue service with the inside furnished to simulate the lower floor of

1026-452: A single track is involved, the signal is normally mounted on a post or mast which displays the arm or signal head at some height above the track, in order to allow it to be seen at a distance. The signal is normally placed on the engine driver 's side of the track. When multiple tracks are involved, or where space does not permit post mounting, other forms are found. In double track territory one may find two signals mounted side by side on

1083-419: A speed within sighting distance of the stop signal. Under timetable and train order operation, the signals did not directly convey orders to the train crew. Instead, they directed the crew to pick up orders, possibly stopping to do so if the order warranted it. Signals are used to indicate one or more of the following: Signals can be placed: 'Running lines' are usually continuously signalled. Each line of

1140-455: A structure such as a retaining wall , bridge abutment, or overhead electrification support. Electric lamps for railway signals are often fitted with twin filaments , so that if one burns out, the other keeps the signal lit. A more complicated version of this, such as in the SL35 lamp, a filament changeover relay is fitted in series with the first filament, where if the first filament burns out,

1197-535: A train using both power cars of the TGV POS trainset number 4402 set a new world speed record for travel on conventional rails. The Project V150 train reached 574.8 km/h (357.2 mph). As part of a series of increasingly faster runs that culminated in the official record attempt, it set an unofficial speed record of 554.3 km/h (344.4 mph) on 13 February 2007. Between the TGV POS power cars were three specially modified Duplex cars. The cars closest to

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1254-470: Is broken, the arm will move by gravity into the horizontal position. In the U.S., semaphores were employed as train order signals, with the purpose of indicating to engineers whether they should stop to receive a telegraphed order, and also as simply one form of block signalling. The introduction of electric light bulbs made it possible to produce colour light signals which were bright enough to be seen during daylight, starting in 1904. The signal head

1311-584: Is numbered in the 4400 series. The livery is the same as that of TGV Réseau sets (silver and blue). From 2013 to 2019, all of the TGV POS trainsets were shifted from LGV Est to the TGV Lyria service (a joint-venture by SNCF and the Swiss Federal Railways ) between France and Switzerland , replacing the nine TGV Sud-Est trainsets that had been used. Since 2019, all TGV POS trainsets operate strictly on domestic services. On 3 April 2007

1368-490: Is one where the position of the lights, rather than their colour, determines the meaning. The aspect consists solely of a pattern of illuminated lights, which are all of the same colour. In many countries, small position light signals are used as shunting signals, while the main signals are of colour light form. Also, many tramway systems (such as the Metro of Wolverhampton) use position light signals. A system combining aspects of

1425-431: Is particularly useful on high speed railways . In the absence of lineside signals, fixed markers may be provided at those places where signals would otherwise exist, to mark the limit of a movement authority. Usually, signals and other equipment (such as track circuits and level crossing equipment), are powered from a low voltage supply. The specific voltage varies with the country and equipment used. The reason behind this

1482-408: Is the portion of a colour light signal which displays the aspects. To display a larger number of indications, a single signal might have multiple signal heads. Some systems used a single head coupled with auxiliary lights to modify the basic aspect. Colour light signals come in two forms. The most prevalent form is the multi-unit type, with separate lights and lenses for each colour, in the manner of

1539-414: Is the visual appearance of the signal; the indication is the meaning. In American practice the indications have conventional names, so that for instance "Medium Approach" means "Proceed at not exceeding medium speed; be prepared to stop at next signal". Different railroads historically assigned different meanings to the same aspect, so it is common as a result of mergers to find that different divisions of

1596-432: Is to widen the train but is generally not practicable due to loading gauge restrictions. Running two trainsets coupled together in multiple-unit (MU) configuration provides extra capacity, but required very long station platforms . Given length and width restrictions, the remaining option is to adopt a bi-level configuration, with seating on two levels, adding 45% more passenger capacity. TGV Duplex sets are often run with

1653-562: The London and Croydon Railway (later the Brighton) at New Cross Gate , southeast London, in 1841. It was similar in form to the optical telegraphs then being replaced on land by the electric telegraph . Gregory's installation was inspected and approved for the Board of Trade by Major-General Charles Pasley . Pasley had invented a system of optical telegraphy through semaphores in 1822 for

1710-632: The asynchronous motors , first used on the Eurostar e300 trainsets, which allow an individual motor in a bogie to be isolated (disconnected) in case of failure, allowing the train to continue to operate. Second was the addition of the European Rail Traffic Management System (ERTMS). A total of 50 Dasye trainsets were ordered, with a prototype power car first delivered in late 2006 for testing, before entering service on 14 February 2008. Starting in 2013, many of

1767-617: The 19 Réseau Duplex trainsets. The tri-current function was necessary for the LGV Est , which ends at the German border, where the electrification switches to the 15 kV  16.7 Hz AC system. Meanwhile, the heavily congested lines where the Réseau trainsets were used needed the additional passenger capacity provided by the Duplex passenger carriages. The project allowed SNCF to receive

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1824-604: The British military, and appears to have suggested to Gregory the application of the semaphore to railway signaling. The semaphore was afterwards rapidly adopted as a fixed signal nearly universally. Disc signals, such as those made by the Hall Signal Company , were sometimes used, but semaphores could be read at much longer distances. The invention of the electric light , which could be made brighter than oil lamps and hence visible both by night and day, resulted in

1881-527: The Dasye trainsets have been reconfigured for use on SNCF's low-cost Ouigo service. These trains use a high-density layout, which can carry 20% more passengers (644 passengers, compared to 510 on a standard trainset). The extra seating is enabled by the elimination of the bar car and first-class cars, and the use of slimline seats. By 2021, 38 Dasye trainsets have been converted for Ouigo service, with all 50 trainsets expected to be converted by 2025. Eurotrain

1938-434: The Réseau trainsets. The tri-current function was necessary for the LGV Est , which ends at the German border, where the electrification switches to the 15 kV  16.7 Hz AC system. Meanwhile, the heavily congested lines where the Réseau trainsets were used needed the additional passenger capacity provided by the Duplex passenger carriages. The project allowed SNCF to receive the tri-current power cars needed ahead of

1995-516: The TGV Duplex order. For the POS project, Alstom delivered to SNCF 38 new tri-current power cars and 19 sets of double-deck Duplex passenger carriages in 2006. The new tri-current power cars were paired with the 19 sets of older single-level passenger carriages from TGV Réseau trainsets, while the new double-deck Duplex passenger carriages were paired with the 38 older dual-current power cars, creating

2052-550: The TGV Duplex started as a small component of the TGV fleet, it has become one of the system's workhorses. A total of 160 Duplex trainsets were built: the original order of 89 first constructed in 1995, an additional 19 Réseau Duplex trainsets created as an extension of the TGV POS project in 2006, and 52 second-generation Dasye trainsets were first delivered in 2007 with revised traction motors and safety systems. The Duplex design

2109-520: The colour and position systems was developed on the Baltimore and Ohio Railroad (B&O) in 1920 and was patented by L.F. Loree and F.P. Patenall. It is similar to the position light system with the central light removed and the resulting pairs of lights colored in correspondence to the angle they make: green for the vertical pair, amber for the right diagonal pair, and red for the horizontal pair. An additional pair, colored "lunar white", may be added on

2166-472: The development of position light signals and colour-light signals at the beginning of the 20th century, which gradually displaced semaphores. A few remain in modern operations in the United Kingdom. Mechanical signals may be operated manually, connected to a lever in a signal-box, by electric motors, or hydraulically. The signals are designed to be fail-safe so that if power is lost or a linkage

2223-643: The disadvantage of having moving parts which may be deliberately tampered with. This had led to them becoming less common during the last fifteen to twenty years when vandalism began to render them vulnerable to false indications. However, in some other countries, such as on the Italian railways ( FS ) as from the Regolamento Segnali , they are still the standard colour light signal albeit with new installations being as outlined below. More recently, clusters of LEDs have started to be used in place of

2280-418: The double-decker design has improvements in both power-to-weight ratio and weight-per-seat overhead: In this comparison, "power" refers to installed power, not all of which is used when operating. Also unique compared to single-level equipment, the lower level of the bar car is used for equipment, moving them out of passenger spaces. The Réseau Duplex was part of the TGV POS project, a unique extension of

2337-465: The driver to stop. Originally, signals displayed simple stop or proceed indications. As traffic density increased, this proved to be too limiting and refinements were added. One such refinement was the addition of distant signals on the approach to stop signals. The distant signal gave the driver warning that they were approaching a signal which might require a stop. This allowed for an overall increase in speed, since train drivers no longer had to drive at

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2394-481: The first rake of eight trailers was tested at 290 km/h (180 mph) on the Sud-Est line. The trainset was powered by TGV Réseau power cars at the time, as the Duplex power cars were not ready. The first Duplex power car was mated to the bi-level trailers on 21 June 1995. Perhaps the most important innovation is the efficiency of the Duplex design. Comparing an original TGV Sud-Est and a Duplex trainset shows that

2451-442: The incandescent lamps, reflectors and lenses. These use less power and have a purported working life of ten years, but this may not in reality be the case. Operating rules generally dictate that a dark signal be interpreted as giving the most restrictive indication it can display (generally "stop" or "stop and proceed"). Many colour light systems have circuitry to detect such failures in lamps or mechanism. A position light signal

2508-613: The intermediate cars of TGV Duplex trainset #224 was joined with German Railways ICE 2 powerheads 402 042 and 402 046 at the two ends. On 4 May 1998, the Eurotrain demonstration train made a presentation run on the Hanover–Würzburg high-speed railway in Germany, achieving a maximum speed of 316 km/h (196 mph). In December 2000, THSRC awarded the contract to the rival Taiwan Shinkansen Consortium, leading to

2565-434: The lamp. In this manner, gravity (fail safe) returns the red roundel into the lamp's optical path. In effect, this mechanism is very similar to the colour light signal that is included in an electrically operated semaphore signal, except that the omission of the semaphore arm allows the roundels to be miniaturized and enclosed in a weatherproof housing. Widely used in the U.S. from World War II onward, searchlight signals have

2622-465: The locomotive were each fitted with two powered bogies, similar to the AGV prototype, providing four more powered axles than the trainset used during the 1990 TGV world speed record, and had a theoretical maximum power output of 19.6 MW (26,284 hp). The train set ran with larger wheels, and the voltage of the overhead lines was increased to 31 kV from the standard 25 kV. The maximum speed

2679-506: The opening of the LGV Est, without slowing the production of the Duplex trainsets. The TGV POS power cars have a total power output of 9.6  MW (12,874  hp ) under 25 kV 50 Hz AC , and 6.8 MW (9,119 hp) under 15 kV 16.7 Hz AC, with a top speed of 320 kilometres per hour (199 mph) under either system. Each TGV POS trainset weighs 383 t (377 long tons; 422 short tons) and

2736-409: The other diagonal for restricting indications. Speed signalling is indicated not by additional signal heads, but by a system of white or amber "orbital" lights placed in one of six positions above and below the main head. The position above or below indicates the current speed, while the left-to-right position indicates the speed at the next signal (full, medium, or slow in both cases). Dwarf signals have

2793-442: The points or switches, section of track, etc. that they are ahead of. The term "ahead of" can be confusing, so official UK practice is to use the terms in rear of and in advance of . When a train is waiting at a signal it is "in rear of" that signal and the danger being protected by the signal is "in advance of" the train and signal. In North American practice, a distinction must be made between absolute signals, which can display

2850-466: The presence of trains and alter signal aspects to reflect their presence or absence. Some locomotives are equipped to display cab signals . These can display signal indications through patterns of lights in the locomotive cab, or in simple systems merely produce an audible sound to warn the driver of a restrictive aspect. Occasionally, cab signals are used by themselves, but more commonly they are used to supplement signals placed at lineside. Cab signalling

2907-466: The relay drops and lights the second filament. This filament fail relay also activates an alarm in the signal box. When lamps fail, this can result in aspects that are less restrictive (high speed) than when the lamps are correctly lit. This is potentially dangerous. For example, in UK practice, if a white "feather" indicator fails, the low speed feather combined with a green light, which is low speed, becomes

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2964-408: The same aspects as full-sized signals. One of the advantages claimed for the system is that burned-out bulbs produce aspects which can be interpreted unambiguously as either the intended indication (for the main head) or as a more restrictive indication (for the orbitals—if only the central head is lit, the indication is either slow or restricting). Colour position lights (CPLs) were first installed as

3021-442: The signals, and later by levers grouped together and connected to the signal by wire cables, or pipes supported on rollers (US). Often these levers were placed in a special building, known as a signal box (UK) or interlocking tower (US), and eventually they were mechanically interlocked to prevent the display of a signal contrary to the alignment of the switch points. Automatic traffic control systems added track circuits to detect

3078-418: The tri-current power cars needed ahead of the opening of the LGV Est, without slowing the production of the Duplex trainsets. Dasye is a contraction of Duplex Asynchronous ERTMS and are the second generation of Duplex trains. In exterior design and passenger cabin experience, they are nearly identical to the first-generation Duplex trains, however, two major changes were made inside the power cars. First were

3135-483: Was a consortium formed by Siemens and GEC-Alsthom (today Alstom ) in 1996 to market high-speed rail technology in Asia. In 1997, it was one of two competitors to supply the core system of Taiwan High Speed Rail (THSR), and was awarded the status of preferred bidder by concessionaire THSRC. In early 1998, the consortium created a demonstration train by combining cars of three existing French and German high-speed trains:

3192-634: Was achieved near kilometer post 193 on the LGV Est between Meuse and the Champagne-Ardenne TGV stations. TGV Duplex The TGV Duplex is a French high-speed train of the TGV family, manufactured by Alstom , and operated by the French national railway company SNCF . They were the first TGV trainsets to use bi-level passenger carriages with a seating capacity of 508 passengers, increasing capacity on busy high-speed lines. While

3249-487: Was further refined into the third generation Euroduplex . The LGV Sud-Est from Paris to Lyon is the busiest high-speed line in France. After its opening in 1981 it rapidly reached capacity. Several options were available to increase capacity. The separation between trains was reduced to three minutes on some TGV lines, but the increasingly complex signalling systems, and high-performance brakes (to reduce braking distance ) required, limited this option. Another option

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