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Type H Tightlock couplers are a variety of Janney coupler, typically used on North American mainline passenger rail cars. They have mechanical features that reduce slack in normal operation and prevent telescoping in derailments, yet remain compatible with other Janney types used by North American freight railroads.
Like all Janney couplers, the Tightlock is "semi-automatic". The couplers automatically lock when cars are pushed together, but workers must go between cars to hook up the air lines for the pneumatic brakes and connect cables for head-end power and other communications. To separate cars, a worker must use a lever to move the locking pin that keeps the coupler closed.
In Europe, some operators experimented with making fully automatic tightlock couplers by adding integral pneumatic and electric connectors, but these connections proved unreliable, and most have switched to the more common fully automatic Scharfenberg coupler.
Janney Type H Tightlock coupler standards were established by the Association of American Railroads, which transferred the standard to the American Public Transportation Association in 1971 when passenger service was nationalized in the United States from most private railway companies to Amtrak.
On a standard-gauge railway, the nominal mounting height for the coupler (rail top to coupler center) is 33 inches (838 mm), with a 34+1⁄2 ± 1 inch (876 ± 25 mm) maximum height on empty cars and 31+1⁄2 ± 1 inch (800 ± 25 mm) minimum height on loaded cars. [1]
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AAR Type F Vertical InterLock couplers, [2] often mistaken for the Type H Tightlock, are another variety, typical on North American gondola wagons that go through rotary dumpers.
Type H couplers are in widespread use on multiple unit passenger trains in the UK built from the mid 1970s onwards. The previous generation of slam door units fitted with Buckeye/Henricot couplers had required a shunter to get down onto the track and stand between the two units to manually trip the coupler mechanism as well as connect or disconnect the air pipes and electrical jumper leads. In order to reduce staffing costs and cut down station dwell times, British Rail looked to incorporate an automatic coupler mechanism in its new power-door trains. Class 313 units were the first stock to incorporate this. Air-operated Tightlock couplers were chosen, together with underslung electrical connector boxes controlled by a Drum switch, and this allowed drivers to single-handedly attach or split a train without having to leave the cab.
Classes of train equipped included:
Tightlock was generally a success in the UK, but there were reliability issues and some notable incidents occurred where trains divided in service. The constant couple-uncouple cycles of heavy London commuter services caused the couplers' mechanisms to wear out faster than expected. Connex South Eastern's Networker fleet was particularly susceptible to this and the company blamed its drivers in the media, [3] then changed its coupling instructions to drivers to include a "push-on, pull off" power test and visual inspection to ensure that the knuckles had engaged fully.
By the early 2000s the first batch of Bombardier Electrostar Class 375s had been built with Tightlock couplers for Connex South Central and Connex South Eastern, but it was quickly decided that Dellner couplings would be preferable. All subsequent units were built with these, and their earlier examples were eventually modified.
All multiple-unit trains built for the UK since then have been equipped with Dellner couplings.
A railway air brake is a railway brake power braking system with compressed air as the operating medium. Modern trains rely upon a fail-safe air brake system that is based upon a design patented by George Westinghouse on April 13, 1869. The Westinghouse Air Brake Company was subsequently organized to manufacture and sell Westinghouse's invention. In various forms, it has been nearly universally adopted.
Multiple-unit train control, sometimes abbreviated to multiple-unit or MU, is a method of simultaneously controlling all the traction equipment in a train from a single location—whether it is a multiple unit comprising a number of self-powered passenger cars or a set of locomotives—with only a control signal transmitted to each unit. This contrasts with arrangements where electric motors in different units are connected directly to the power supply switched by a single control mechanism, thus requiring the full traction power to be transmitted through the train.
The British Rail Class 377 Electrostar is a British dual-voltage electric multiple unit passenger train (EMU) built by Bombardier Transportation on its Electrostar platform at Derby Litchurch Lane Works from 2001 to 2014.
A coupling or coupler is a mechanism, typically located at each end of a rail vehicle, that connects them together to form a train. The equipment that connects the couplers to the vehicles is the draft gear or draw gear, which must absorb the stresses of the coupling and the acceleration of the train.
RoadRailers were a trailer or semi-trailer that could be hauled on roads by a tractor unit and then by way of a fifth wheel coupling, operate in a unit train on railway lines. The RoadRailer system allowed trailers to be pulled by locomotives without the use of flatcars, instead attaching trailers directly to bogies.
The British Rail Class 171 Turbostar is a type of diesel multiple unit (DMU) passenger train built by Bombardier Transportation at Derby Litchurch Lane Works in England. It is identical to the Class 170, except for the replacement of the BSI coupler with a Dellner coupler. This provision was made to allow emergency joining with Class 377 DC third-rail electric units, which Southern runs extensively on most lines. The units work on the southern regions of the British railway system, operating services from London Bridge to Uckfield and from Eastbourne to Ashford International, these routes being unelectrified between Hurst Green Junction and Uckfield and between Ore and Ashford International, respectively.
A rotary car dumper or wagon tippler (UK) is a mechanism used for unloading certain railroad cars such as hopper cars, gondolas or mine cars. It holds the rail car to a section of track and then rotates the track and car together to dump out the contents. Used with gondola cars, it is making open hopper cars obsolete. Because hopper cars require sloped chutes in order to direct the contents to the bottom dump doors (hatches) for unloading, gondola cars allow cars to be lower, thus lowering their center of gravity, while carrying the same gross rail load. Cars are equipped with rotary couplers to allow dumping them while they are still coupled; a "Double Rotary" gondola or hopper has rotary couplers on both ends to allow it to be unloaded while it remains coupled to stationary cars at each end.
Rail freight transport is the use of railways and trains to transport cargo as opposed to human passengers.
The Scharfenberg coupler is a commonly used type of fully automatic railway coupling.
SA3 couplers or Willison coupler and Russian coupler are railway couplings used primarily in Russia and states influenced by the former Soviet Union, such as Finland, Poland, and Mongolia.
In railroading, slack action is the amount of free movement of one car before it transmits its motion to an adjoining coupled car. This free movement results from the fact that in railroad practice cars are loosely coupled, and the coupling is often combined with a shock-absorbing device, a "draft gear", which, under stress, substantially increases the free movement as the train is started or stopped. Loose coupling is necessary to enable the train to bend around curves and is an aid in starting heavy trains, since the application of the locomotive power to the train operates on each car in the train successively, and the power is thus utilized to start only one car at a time.
The railcar couplers or couplings listed, described, and depicted below are used worldwide on legacy and modern railways. Compatible and similar designs are frequently referred to using widely differing make, brand, regional or nick names, which can make describing standard or typical designs confusing. Dimensions and ratings noted in these articles are usually of nominal or typical components and systems, though standards and practices also vary widely with railway, region, and era. Transition between incompatible coupler types may be accomplished using dual couplings, a coupling adapter or a barrier wagon.
A barrier vehicle (BV), barrier wagon, match wagon or translator coach is used to convert between non-matching railway coupler types. This allows locomotives to pull railway vehicles or parts of a train with a different type of coupler. A match wagon has an identical dual coupling at both ends.
The C-AKv is a fully automatic coupler design, also known as the Faiveley Transpact; it is a hybrid compatible with both buffers and chain couplers and Russian SA3 couplers, intended as an option for the long delayed EU transition to center buffer couplers. C-AKv is an abbreviation of Compact Automatische Kupplung vereinfacht in German, translating to Compact Automatic Coupler simplified in English.
A gangway connection is a flexible connector fitted to the end of a railway coach, enabling passengers to move between coaches without danger of falling from the train.
Knuckle couplers are a semi-automatic form of railway coupling that allow rail cars and locomotives to be securely linked together without rail workers having to get between the vehicles.
From time to time, a railway decides that it needs to upgrade its coupling system from one that is proving unsatisfactory, to another that meets future requirements. This can be done gradually, which can create many problems with transitional incompatibilities, or overnight, which requires much planning.
Dellner Couplers AB is a Swedish original equipment manufacturer of train connection systems such as couplers, gangway systems and dampers. The headquarter of the company is in Vika in the Falun Municipality. Dellner is owned by the investment organisation EQT AB and has 19 subsidiaries worldwide, with around 1,100 employees. In 2018, the company generated annual sales of around SEK 1.9 billion.
Buffers and chain couplers – also known as "buffers and screw", "screw", and "screwlink" – are the de facto International Union of Railways (UIC) standard railway coupling used in the EU and UK, and on some railways in other parts of the world, such as in South America and India, on older rolling stock. Buffers and chain couplers are an assembly of several devices: buffers, hooks and links, or turnbuckle screws.
Different types of railroad rolling stock have different couplers depending on the purpose and type of equipment being used and its intended destination. European rolling stock tend to use buffers and chain couplers while American rolling stock uses a Janney coupler or "knuckle coupler". These are incompatible with each other, but where some railroads have obtained older, less expensive used rolling stock from different countries or regions, instead of having to standardize on one form of coupler, it may be useful to be able to use either type of coupler on a piece of rolling stock without having to remove anything.