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47-558: ATB operates by the train collecting electrical signals from line-side apparatus and will override the driver's controls in the following situations: ATB-EG ( ATB E erste G eneratie English: ATB First Generation ) is based on the American Pulse Code Cab Signaling system. It is installed on all major Dutch rail lines. ATB-EG controls 5 speeds: 40 km/h, 60 km/h, 80 km/h, 130 km/h and 140 km/h. Just like Pulse Code Cab Signaling

94-515: A Restricting signal. The codes would be transmitted to the train from the block limit in front of it. This way if the rail was broken or another train entered the block, any codes would not reach the approaching train and the cab signal would again display Restricting. Trains with an insufficient number of axles will not short out (see: Shunt (electrical) ) all of the cab signal current so that following trains might receive an incorrect aspect. Trains of this type must be given absolute block protection to

141-431: A red signal as the system thinks the train has already passed the signal, while it might still be several meters away. Another problem is the fact that ATB-NG can't react to signal changes. If a red signal clears ATB-NG will still force the train to stop and only let it creep forward until it reaches the next beacon. This issue can however be solved by installing ATB loops which enable the system to pick up signal updates in

188-513: A signaling technology that could improve both safety and operational efficiency by displaying a signal continuously in the locomotive cab. The task was assigned to Union Switch and Signal corporation, the PRR's 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

235-545: A stretch of track before the signal. An issue with the ATB-NG system as a product is the patent held by ACEC - Alstom , which limits other manufacturers to supply the system and the fact that it offers poor interoperability with other systems. The implementation is shown in the map above. Beside intermediately closing of functional gaps, new constructed lines will use European Train Control System (ETCS) as part of

282-491: A train to drive 130 km/h in a 90 km/h zone. Another drawback is the maximum speed being set to 140 km/h. Tracks with a design speed of up to 160 km/h cannot be used up to full speed because ATB-EG does not allow this. This is becoming more of an issue with the ever-growing rail traffic. ATBM+ has later been developed to raise this speed to 160 km/h. Vossloh G2000 locomotives equipped with ATB EG suffer from some unwanted emergency brake applications. This

329-465: Is also able to receive ATB-EG signals, making the system backwards compatible . Because major, electrified routes received priority when installing ATB-EG, ATB-NG is almost exclusively found on diesel-lines as these were the only unprotected routes when the system came out. One exception is the former diesel line between Zwolle and Wierden which was electrified between 2016 and 2017. The system works by conveying movement authorization via balises between

376-501: Is because the brake pipe pressure, on which the brake criterion is based, takes 4 to 5 seconds to drop, while the ATB intervenes in 3 seconds. FLIRT trains have the same problem as the G2000 locomotives, because their brake criterion is based on the brake cylinder pressure. Additionally the brake criterion can "vanish" when the anti-lock braking system engages, because the system could reduce

423-409: Is designed to reduce " Stoptonend Sein (STS)-passages" (English: Signals Passed At Danger ) by applying an emergency brake after passing a signal at danger. It compensates the original design flaws in speeds below 40 km/h where no forced braking was possible in case of passing stop signals. ATB-Vv ( V erbeterde v ersie English: Improved version ) is the latest evolution of ATB-Plus-Plus. It

470-413: Is enhanced with three beacons in distance of 120, 30 and 3 m before the attributed signal, using technology comparable with German PZB . After activation by ATB-Vv the movement of the train is self-controlled with regard to the braking curve. So the chance of a " Stoptonend Sein (STS)-passages" (English: Signals Passed At Danger ) is minimal. The system is not fail-safe as a broken beacon will result in

517-407: Is interpreted as the most restrictive signal, making the system fail-safe. To allow driving on sight onto occupied track, which cannot be discerned from passing a red signal using a system like this, receiving no signal was chosen to be interpreted as a speed limit of 40 km/h. ATB-EG has a number of drawbacks when compared to modern systems like ETCS One of the early system's design limitations

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564-444: The speedometer , as cab signals now serve a speed control function. On trains equipped with automatic train control functionality failure to properly acknowledge a restrictive cab signal change results in a 'penalty brake application', as does failure to observe the cab signal speed limit. Vossloh G2000 BB The G 2000 BB is a four axle heavy shunting and mainline locomotive, designed by German company Vossloh and built at

611-433: The 250 Hz codes get upgraded speeds on track sections with speeds greater than 125 mph and on 80 mph high speed turnouts. Trains without simply travel at the slower speeds. The 270ppm code does break backwards compatibility with the 4-code system, but is only in use around New York Penn Station as part of a high density signaling upgrade. The 270ppm code and 60 mph speed were chosen to be compatible with

658-449: The ATB will initiate an emergency brake application. The system will stop the warning once the driver is braking sufficiently, this is checked by means of the so-called remcriterium (English: brake criterion). The remcriterium is based on either the brake pipe pressure, brake cylinder pressure or the position of the brake lever. This should ensure the train reaches the target speed before the next block, but it often proves inadequate. When

705-460: The PRR installed cab signals over much of its eastern system from Pittsburgh to Philadelphia, New York to Washington. This system was then inherited by Conrail and Amtrak and various commuter agencies running on former PRR territory such as SEPTA and New Jersey Transit . Because all trains running in cab signal territory had to be equipped with cab signals, most locomotives of the aforementioned roads were equipped with cab signal equipment. Due to

752-539: The PRR tested another variation of cab signals which dropped the loop signal and switched to 100 Hz for the track signal. 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. This new system allowed four signal aspects: Restricting; Approach; Approach (next signal at) Medium (speed); and Clear. Initially

799-597: The assigned standard ERTMS . ETCS is already in use on Betuweroute line and HSL-Zuid . Pulse code cab signaling 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. The 4-aspect system widely adopted by the PRR and its successor railroads has become

846-447: The brake pressure below the point to comply with the brake criterion. This will also result in an emergency brake application. Over the years multiple enhancements were introduced to overcome some of the system's flaws. ATBM+ is designed to raise the maximum speed from 140 to 160 km/h. This system is only installed on line between Hoofddorp and Den Haag Mariahoeve and is currently solely used by Thalys trains ATB-Plus-Plus

893-469: The cab signaling system only acted as a form of automatic train stop where the engineer would have to acknowledge any drop in the cab signal to a more restrictive aspect to prevent the brakes from automatically applying. Later, passenger engines were upgraded with speed control which enforced the rulebook speed associated with each cab signal (Clear = No Restriction, Approach Medium = 45 mph, Approach = 30 mph, Restricting = 20 mph). Over time

940-539: The cab signals installed on the Long Island Rail Road trains that also use Penn Station. Cab signals are presented to the locomotive by means of a cab signal display unit. The earliest CDUs consisted of miniature signals of the type visible along the track, back lit by light bulbs. These could be found in both color light and position light varieties depending on the railroad's native signaling system. Modern CDUs on passenger trains are often integrated with

987-456: The cab these two models are identical to the initial asymmetric offering. Starting in 2004, two further sub designs were made: G 2000-4 BB with a MTU engine which increase the power to 2700 kW. This variant also included a hydrodynamic retarder (a type of braking system) as part of the Voith supplied transmission package. The last variant is G 2000-5 BB which has the same upgrades as

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1034-852: The dominant railroad cab signaling system in North America with versions of the technology also being adopted in Europe and rapid transit systems. In its home territory on former PRR successor Conrail owned lines and on railroads operating under the NORAC Rulebook it is known simply as Cab Signaling System or CSS . In 1922 the Interstate Commerce Commission issued a ruling requiring trains to be equipped with automatic train stop technology if they were to be operated at 80 mph or greater. The Pennsylvania Railroad decided to use this as an opportunity to implement

1081-411: The effect of interoperability lock in, the 4-aspect PRR cab signal system has become a de facto standard and almost all new cab signaling installations have been of this type or a compatible type. Pulse code cab signals work by sending metered pulses along an existing AC track circuit operating at a chosen carrier frequency . The pulses are detected via induction by a sensor hanging a few inches above

1128-488: 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. For its next installation, on the Northern Central line between Baltimore, MD and Harrisburg, PA in 1926 (1927?),

1175-602: The former MaK plant in Kiel . At the time of its introduction in 2000 it was the most powerful hydraulic transmission locomotive in Vossloh's range. The locomotive was unveiled at Innotrans in 2000. The initial model had an asymmetric cab (see image) with a walkway; the asymmetric cab design allows the walkway to extend all the way to each end of the locomotive; coupled with remote control operation this means that shunting can be done from an external viewpoint whilst still riding on

1222-541: The fourth offering, it is designed for the Scandinavian market and as such has anti wheel slip technology, and can be equipped for service down to −40 °C (−40 °F). The locomotives are certified for use on the railways of Germany, Switzerland, Italy, Netherlands, Belgium, France, Sweden, Denmark and Poland. The locomotives are operated by many companies, many of them on lease. Angel Trains and MRCE both act as leasing companies, with Angel Trains providing

1269-631: The locomotive. The design is modular with various components (engine, drive etc.) coming from different suppliers. External styling was by Tricon-Design. A second variant was produced, this time with a symmetrical cab; two different versions of this model were produced - one for the Italian market ( G 2000-2 BB ) with left hand drive (trains in Italy generally keep to the left) and another ( G 2000-3 BB ) with right hand drive for Germany. The new cabs had seating for two operators, in other respects apart from

1316-413: The outside of the speedometer. The driver will be informed of a speed change with a short "ding". If the driver exceeds the current ATB-speed by 5 km/h a bell will start to ring continuously. If the driver does not brake within 3 seconds the ATB will initiate an emergency brake application. When a stretch of track has an ATB code for a lower speed, due to a lower track speed or a diverging switch etc.,

1363-406: The overlay codes, backwards compatibility could be maintained so that any train unable to detect the new codes would never receive a signal more favorable than had it would otherwise detect. In addition to the use of 250 Hz codes, a 5th, 270ppm code was incorporated from rapid transit and Long Island Rail Road use. The mapping of codes to speeds is as follows: Trains with the ability to get

1410-472: The problem and avoid a complete rebuild of the signaling system, impair lower speed service, break backwards compatibility with existing cab signals or place too high a reliance on the human operator, an overlay pulse code system was devised for use on Amtrak's Northeast Corridor. By operating with a different carrier frequency of 250 Hz, additional pulse codes could be sent to the train without interfering with legacy 100 Hz codes. By carefully designing

1457-422: The rail before the leading 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

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1504-476: The rear. Where DC and 25 Hz AC electrification co-exist, the standard 100 Hz frequency is changed to 91⅔ Hz (next available M-G set frequency). This avoids even harmonics created by the return rail's DC traction current offsetting the AC return sine wave in the same rail. 70 years after pulse code cab signals had been introduced, the 4 speed design was found to be insufficient for speeds not envisioned when

1551-406: The red LED will disappear. The exit speed, which has to be reached when the movement authority ends, is displayed by a dot-matrix below the speedometer. An illuminated bar next to the speedometer shows the remaining distance until this speed has to be reached. When the exit speed is the same as the current speed the bar will remain dark. If the movement authority ends before the next beacon is reached,

1598-424: The section before it will carry that code as well. A signal or sign guarding the first section will inform the driver of the oncoming speed reduction and upon entering that block the ATB will change to the target speed. According to the ATB the train is now overspeeding so it will initiate the continuous bell, informing the driver that they need to start braking. Once again, if the driver does not brake within 3 seconds

1645-452: The speedometer. If the train exceeds the maximum speed by more than 2,5 km/h the LED will start to flash and from 5 km/h above the maximum speed a bell will ring. If the maximum speed is exceeded by 7,5 km/h the emergency brakes will be applied. Braking is managed by a brake-curve relative to the weight of the train. When the train approaches the point where it needs to start braking,

1692-441: The system was designed. The two most pressing problems were the use of high speed turnouts , which allowed trains to take a diverging route faster than the normal 30 or 45 mph covered by the existing cab signals. The introduction of Amtrak's Acela Express service with its 135 mph to 150 mph maximum speeds would also exceed the capabilities of the legacy signaling system and its 125 mph design speed. To address

1739-624: The system works by sending pulses along the AC track circuit . When the circuit is closed by the train's front wheels an electromagnetic field is created with each pulse. These fields electromagnetically energise two coils in front of the leading axle which feed the pulses to the ATB-system. The onboard ATB system works out the amount of pulses per minutes and translates this to the 5 codes Yellow, Yellow6, Yellow8, Yellow13 and Green with corresponding speeds of 40, 60, 80, 130 and 140 km/h or so-called volle materieelsnelheid (full train speed). If

1786-480: The time it was deemed unlikely a driver would miss a red signal when traveling below 40 km/h and expecting one. It is seen as a problem now as numerous accidents have occurred and safety regulations became stricter over time. The gaps between each speed setting form a problem. If there is no matching speed setting for the current speed limit, the next speed setting above it will be enforced. The biggest gap falls between 80 and 130 km/h, meaning ATB EG will allow

1833-418: The tracks, called beacons, located next to signals and in other strategic places. These beacons are offset towards the left as seen from the driver, making the system directional. The system manages the maximum speed, maximum travel distance, the exit speed and the "release-speed". Speed limits are set in 10 km/h intervals from 0 through 200 km/h and indicated by a yellow LED next to the maximum speed on

1880-439: The train can continue with a specified "release-speed", often 30 km/h, until it receives new authority from the next beacon. One weakness of the system is wheelslip caused by slippery rails . ATB-NG measures the traveled distance by counting the wheel rotations; therefore, the system will think the train is ahead of its actual position when the wheelspin occurs. This can result in premature brake interventions when approaching

1927-406: The train is within the 5 km/h margin of the target speed the system rings three short bells, informing the driver that they are allowed to stop braking. After passing a red signal and entering a section already occupied by another train, the track circuit is already shorted by the other train preventing the signal from reaching the train passing the red signal. Therefore, the absence of a signal

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1974-434: The train not braking automatically. Since 1990 a second generation, ATB-NG ( ATB N ieuwe G eneratie English: ATB New Generation ), has been developed to overcome all the problems posed by ATB-EG. The systems is completely different from ATB-EG and operates nearly equal to ETCS Level 1, ATB-EG and ATB-NG can both can safely be installed at the same track as they do not interfere with each other. Trainborne ATB-NG equipment

2021-515: The train's maximum allowed speed is lower (as for instance the SGM ), the speed settings above its maximum speed will be omitted. (out of order) The speed limit enforced by ATB-EG is presented to the driver by a row of lights, with the current cab signal illuminated, ( Mat 64 , SLT , PROTOS and THALYS ) which can be integrated into speedometer ( ICM and SGM ) or either a red needle ( VIRM , DDAR and Loc 1700 ) or yellow LED ( FLIRT and GTW ) on

2068-613: The vast majority of the leased locomotives. Other owners include Azienda Consorziale Trasporti (ACT) and SBB Cargo (as class SBB Am 840 ) The machines find use in northern Italy and in the German Ruhr region as well as being used for cross border traffic in the Benelux region. Railion , Euro Cargo Rail , Rail4chem and others all use this locomotive. The locomotives are used for freight. In Italy, these are notably owned by TPER, which uses them in some of its cargo services under

2115-408: The yellow LED will jump to the target speed and a red LED will light up at the former position. The red LED will steadily decrease towards the target speed, ensuring the driver brakes accordingly. If the train speed exceeds the red LED by 7,5 km/h a brake application is induced. When the train reaches the target speed three short bells will sound, informing the driver that they can stop braking, and

2162-443: 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 returning 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

2209-418: Was the inability to enforce speeds below 40 km/h. Several accidents at train stations and railroad yards occurred because the driver failed to stop at a red signal and ATB did not intervene, as it had already enforced a speed below 40 km/h. Strange as this limitation may seem, there was a reason for it. The main purpose of ATB was to prevent overspeeding and failing to respond to yellow signals, at

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