Flexicoil suspension is a type of secondary suspension for railway vehicles, typically having steel coil springs between the bogie trucks and chassis/frame of a passenger coach, goods freight wagon, or locomotive. Suspension systems using steel springs are more common than those with air springs, as steel springs are less costly to make, relatively wear resistant, and require less maintenance.
Flexicoil (though not known by this term) suspensions were fitted to locomotives in Spain, the Soviet Union and Africa as early as the 1930s. [1] In Germany, Flexicoil suspensions were first used in the 1950s under high-speed electric locomotives, notably the DB Class 103. [2]
Between 1969 and 1971, British Rail conducted tests of modified Flexicoil bogies under a modified Class 86, to prevent further track damage caused by the original Class 86 bogies; tests were successful and all Class 86 locomotives were refitted with the modifications in stages through the 1970s and 1980s. [2] [3] [4]
The springs in a flexicoil suspension are made of steel. Protruding from above and below, and into, each spring is a spherical rubber dome that can absorb some of the horizontal forces. These domes are connected firmly to either the vehicle body (above) or the bogie frame (below). Under this arrangement, each flexicoil spring is twisted and moved from its vertical axis when the vehicle is cornering. This helps the two bogies to align themselves equally underneath the vehicle body. The vertical forces are absorbed entirely by the steel springs.
As the springs have relatively soft characteristics, hydraulic vertical dampers must also be installed for vibration damping at speeds higher than 160 km/h (99 mph), along with longitudinal dampers. Lateral damping is not normally required.
In railway passenger cars fitted with flexicoil suspension, the springs are the only mechanical connection between the bogie and the car body. In heavier types of flexicoil suspension rolling stock, a bogie pivot fitted with rubber-metal bearings is used to hold a cross anchor yoke, which transfers the forces to the bogie frame via two cross anchor link pins. Some, such as the Italian D.445 class, have additional traction rods. [5]
Locomotive bogies are usually also provided with a weight transfer linkage, or with a different tension transmission.
A bogie is a chassis or framework that carries a wheelset, attached to a vehicle—a modular subassembly of wheels and axles. Bogies take various forms in various modes of transport. A bogie may remain normally attached or be quickly detachable. It may include a suspension component within it, or be solid and in turn be suspended ; it may be mounted on a swivel, as traditionally on a railway carriage or locomotive, additionally jointed and sprung, or held in place by other means.
A shock absorber or damper is a mechanical or hydraulic device designed to absorb and damp shock impulses. It does this by converting the kinetic energy of the shock into another form of energy which is then dissipated. Most shock absorbers are a form of dashpot.
Suspension is the system of tires, tire air, springs, shock absorbers and linkages that connects a vehicle to its wheels and allows relative motion between the two. Suspension systems must support both road holding/handling and ride quality, which are at odds with each other. The tuning of suspensions involves finding the right compromise. It is important for the suspension to keep the road wheel in contact with the road surface as much as possible, because all the road or ground forces acting on the vehicle do so through the contact patches of the tires. The suspension also protects the vehicle itself and any cargo or luggage from damage and wear. The design of front and rear suspension of a car may be different.
HS4000 Kestrel was a prototype high-powered mainline diesel locomotive that was built in 1967 by Brush Traction, Loughborough, as a technology demonstrator for potential future British Rail and export orders. The locomotive number is a combination of the initials of Hawker Siddeley and the power rating of its Sulzer diesel engine (4,000 hp), making it the most powerful locomotive built by the company.
The DB Class 101 is a class of three-phase electric locomotives built by Adtranz and operated by DB Fernverkehr in Germany. 145 locomotives were built between 1996 and 1999 to replace the 30-year-old and aging Class 103 as the flagship of the Deutsche Bahn, primarily hauling Intercity services. This class encompasses the latest generation of locomotives of the Deutsche Bahn.
A motorcycle's suspension serves a dual purpose: contributing to the vehicle's handling and braking, and providing safety and comfort by keeping the vehicle's passengers comfortably isolated from road noise, bumps and vibrations.
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The High Speed Freight Vehicle was a generic term for a number of prototype four-wheeled rail vehicles which were fitted with various experimental suspensions developed by the British Rail Research Division in the late 1960s. The development was part of the investigation into the riding of vehicles and the interaction between wheel and rail.
The Voith Maxima locomotives are a family of diesel-hydraulic locomotives built by Voith Turbo Lokomotivtechnik GmbH & Co. KG., a subsidiary of Voith.
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Jaguar's independent rear suspension (IRS) unit has been a common component of a number of Jaguar production cars since 1961, passing through two major changes of configuration up to 2006 and last used in the Jaguar XK8 and Aston Martin DB7. This article concentrates on the first generation Jaguar IRS, which firmly established the marque's reputation for suspension sophistication, combining as it did smooth ride with excellent roadholding and low levels of noise, vibration, and harshness (NVH). The two generations overlap in time due to their being used in both full size and sports models that were updated at different times.
The Class D.445 is a class of diesel locomotives used by the Italian Ferrovie dello Stato (FS) railway company and by Trenord. 150 units were built between 1974 and 1988, divided into three series.
The Brig-Visp-Zermatt-Bahn ABDeh 8/8, now known as the Matterhorn Gotthard Bahn ABDeh 8/8, is a three member class of metre gauge, rack rail, electric multiple units operated until 2002 by the Brig-Visp-Zermatt-Bahn (BVZ), and since then by its successor, the Matterhorn Gotthard Bahn (MGB), in the Canton of Valais, Switzerland.
The EP20 (ЭП20) is a type of 6 axle Bo'Bo'Bo' electric passenger locomotive being built for Russian Railways by Transmashholding's Novocherkassk Electric Locomotive Plant. The locomotive was designed by TRTrans, a joint venture between Transmashholding and Alstom.
Friction disk shock absorbers or André Hartford dampers were an early form of shock absorber or damper used for car suspension. They were commonly used in the 1930s but were considered obsolete post-war.
The Indian locomotive class XB was a 4-6-2 passenger locomotive with a 17-long-ton axle load. It had a lot of problems. It was built with the help of British Engineering Standards Association (BESA). It was up to date as any locomotive in England. It had American 3-point suspension with compensating levers for indifferent tracks in India. The trailing wheels were mounted on a Cartazzi truck as it was for the rest of British Pacifics at the time. Goodall-type drawgear was fitted between engine and tender to facilitate free movement. They still proved to be successful as they survived till the 1980s. The modifications in India to this class was implemented in LMS Railway in UK. Copper firebox had combustion chamber extension.
An equalising beam, equalising lever or equalising bar links the suspension of two or more adjacent axles of a vehicle, especially a railway locomotive.
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The Indian locomotive class WDP-1 is a class of diesel-electric locomotive that was developed in 1995 by Banaras Locomotive Works (BLW) for Indian Railways. The model name stands for broad gauge (W), Diesel (D), Passenger traffic (P) engine, 1st generation (1). They entered service in 1995. A total of 69 WDP-1 units were built at Banaras Locomotive Works (BLW), Varanasi between 1995 and 1999.
The DDJ1 is a first generation high-speed electric multiple unit built for China Railway, built by Zhuzhou Electric Locomotives, Changchun Railway Vehicles, Sifang Railway Vehicles, Tangshan Passenger vehicle factory, Nanjing Puzhen and developed by Zhuzhou Electric Locomotive Research Centre. It was built in 1999, and was an experimental vehicle, with only one set built, as it did not enter mass production. The design was well received as part of national science in the 9th five year plan. The DDJ1 is in a push–pull configuration, with only one locomotive in the set and the other end being a trailer with a driver's cabin.
