Head end power (HEP) or Electric train supply (ETS) in the United Kingdom is a rail transport term for the electrical power distribution system on a passenger train. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located "Railroad" and "Railway" both redirect here For other uses see Railroad (disambiguation. The power source, usually a locomotive at the front or “head” of a train or a generator car, generates all the electricity for "hotel" power needed by the train. Hotel Electric Power (HEP is a maritime term referring to electricity generated and used aboard a ship for purposes other than propulsion such as lighting communications climate control
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History
UK
Originally, trains hauled by a steam locomotive would be provided with a supply of steam from the locomotive's boiler for heating the carriages. A steam locomotive is a Locomotive powered by Steam. The term usually refers to its use on Railways but can also refer to a "road locomotive" When diesel locomotives and electric locomotives replaced steam, the steam heating was then supplied by a steam generator. A Diesel locomotive is a type of Railroad Locomotive in which the prime mover is a Diesel engine. "Electric Trains" redirects here For the 1995 Squeeze single see Electric Trains (song. Steam generator is the term used to describe a type of boiler used to produce Steam for climate control and Potable water heating in Railroad This was oil-fired (in diesel locomotives) or heated by an electric element (in electric locomotives).
At this time, lighting was powered by batteries which were charged by a dynamo underneath each carriage when the train was in motion, and buffet cars would use bottled gas for cooking and water heating. In electronics a battery is a combination of two or more Electrochemical cells which store chemical Energy which can be converted into electrical energy In Electricity generation, an electrical generator is a device that converts Mechanical energy to Electrical energy, generally using Electromagnetic A buffet car is a passenger car of a train where snacks and drinks can be bought at a counter and consumed Bottled gas is a term used for substances which are gaseous at Standard temperature and pressure (STP and have been compressed and stored in Carbon steel, Stainless
Later diesels and electric locomotives supplied Electric Train Heating (ETH), which was eventually renamed Electric Train Supply (ETS), to power lighting, heating, ventilation, air conditioning, fans, sockets and kitchen equipment in the train. "Electric Trains" redirects here For the 1995 Squeeze single see Electric Trains (song. The term air conditioning refers to the cooling and dehumidification of indoor air for Thermal comfort. Each coach has an index relating to the maximum consumption of electricity that that coach could use. The sum of all the indices must not exceed the index of the locomotive.
Although most locomotive-hauled trains take power directly from the locomotive, there have been examples (mainly in continental Europe) where restaurant cars would take power directly from the overhead wires. Railway electrification supplies electrical energy to railway Locomotives and Multiple units so they can operate without having a Reciprocating On modern Diesel multiple unit trains, such as the Virgin Trains Voyager, the engine mounted below each vehicle provides power for that vehicle. A diesel multiple unit or DMU is a Multiple unit train consisting of multiple carriages powered by one or more on-board Diesel Virgin Trains is a Train operating company in the United Kingdom, which currently provides services from London Euston to the North West The Class 220 Voyager is a class of Diesel-electric high-speed multiple-unit Trains built by Bombardier Transportation
US
In the days of steam locomotives, cars got their heat from steam supplied by the locomotive. Electricity for train lighting and HVAC came from generators on each car driven either by small engines or by the rotation of the axles. HVAC (pronounced either "H-V-A-C" or occasionally " H-vak " is an Initialism or Acronym that stands for " Heating The first advance beyond these came on steam locomotives and passenger cars assigned to commuter service in Boston by the Boston and Maine Railroad. The Boston and Maine Railroad, also known by the abbreviation B&M, was the dominant Railroad of the northern New England region of the United The B&M found that the passenger cars on commuter trains, with low speeds and short periods of sustained running, did not generate enough electricity from their axle generators to keep their lighting batteries charged. The B&M equipped the steam locomotives assigned to commuter service with larger than usual on-board generators and arranged electrical connections from these to all the cars being pulled in order to keep the batteries charged and lights operating. The cars still depended on steam from the locomotive for heating.
Initially when diesel locomotives were introduced, they incorporated special boilers termed steam generators to heat the existing rolling stock. In the late 1950s the Chicago and North Western Railway replaced the steam generators with diesel generator sets on the F7 and E8 locomotives assigned to pull commuter trains. A diesel generator is the combination of a Diesel engine with an Electrical generator (often called an Alternator) to generate electric energy The EMD F7 was a, B-B Diesel-electric locomotive produced between February 1949 and December 1953 by General Motors ' Electro-Motive Division The EMD E8 was a, A1A-A1A passenger train locomotive manufactured by General Motors ' Electro-Motive Division (EMD of La Grange Illinois. This was a natural evolution as their commuter trains were already receiving low voltage, low amperage power from the locomotives to supplement the electricity from their axle generators in keeping their lighting batteries charged. Sometimes such commuter cars were equipped with propane-engine powered air conditioning. Separate and complex systems of trainlined lighting power, steam heat, and engine-driven air conditioning was ripe for replacement with HEP where a single source provides power for all these functions.
However, while commuter car fleets transitioned to HEP, the intercity trains continued with steam & battery systems. It was only after the coming of Amtrak in 1971, which initially acquired cars and locomotives from the private railroads, that the intercity trains were gradually converted. The National Railroad Passenger Corporation, Doing business as Amtrak, is a Government-owned corporation that was organized on May 1, 1971 All cars ordered new by Amtrak were HEP-equipped and the older cars that were retained were eventually converted during overhauls. Amtrak's initial new-built engines were equipped to pull steam-heated trains. It was not until 1975 when Amfleet cars and F40PH and P30CH locomotives entered service, that large-scale adoption of HEP started in the US. Amfleet are a series of intercity railroad passenger cars built for Amtrak by the Budd Company in two series during the late 1970s and early 1980s The General Motors Electro-Motive Division model F40PH is a 3000 Horsepower (2 The GE P30CH (also nicknamed "POOCH" because of the similarity of the designation was one of the first brand-new Diesel-electric locomotive models built for Amtrak
Engine
The HEP generator can be driven by either a separate engine, mounted in the locomotive or generator car, or by the locomotive's own engine.
Separate engines
Engine types vary, but in the US, they are mainly Caterpillar 3412 V12s and Cummins K-Series Inline 6s. Caterpillars are the Larval form of a member of the order Lepidoptera (the Insect order comprising butterflies and Moths Cummins Inc ( is a corporation of complementary business units that design manufacture distribute and service diesel and Natural gas Engines and related Smaller under-car engines for powering short trains are also manufactured, Stadco being one popular brand of under-car generator.
Locomotive engine
The engine must rotate the HEP generator at a constant speed (rpm) to maintain the required 50 (UK) or 60 (US) Hz AC frequency output. Frequency is a measure of the number of occurrences of a repeating event per unit Time. Therefore, a typical EMD locomotive, in HEP mode, will operate at its full engine speed of 900 rpm, driving the generator at 1500 or 1800 rpm through a gearbox. Electro-Motive Diesel Inc (formerly the Electro-Motive Division of General Motors Corporation is currently the world's second largest builder of Railroad As a noise reduction method, the locomotive's main (traction) generator can also supply HEP, usually at 600 or 720 rpm. However this operating mode is only available when stopped.
The advent of power electronics has allowed the engine to operate over a larger speed range and still supply a constant HEP voltage and frequency by means of inverters. An inverter is an electrical or electro-mechanical device that converts Direct current (DC to Alternating current (AC the resulting AC can be at any required voltage
All power consumed by HEP is at the expense of traction power if powered by the locomotive engine. The 3200 horsepower (2. 4 MW) P32 and the 4000 horsepower (3. The watt (symbol W) is the SI derived unit of power, equal to one Joule of energy per Second. GE Genesis (officially Trademarked GENESIS) is a series of passenger Locomotives produced by GE Transportation Systems, a subsidiary of General 0 MW) Genesis-Series P40 reduce to 2900 (2. GE Genesis (officially Trademarked GENESIS) is a series of passenger Locomotives produced by GE Transportation Systems, a subsidiary of General 2 MW) and 3650 horsepower (2. 72 MW), respectively, when supplying HEP. [1]
Electrical loading
HEP power supplies the lighting, HVAC, dining car kitchen and battery charging loads. HVAC (pronounced either "H-V-A-C" or occasionally " H-vak " is an Initialism or Acronym that stands for " Heating Individual car electrical loading ranges from 20 kW for a typical car to more than 150 kW for a Dome car with kitchen and dining area, such as Princess Tours Ultra-Dome cars operating in Alaska. A dome car is a type of Railway passenger car that has a glass Dome on the top of the car where passengers can ride and see in all directions around Colorado Railcar is a manufacturer of Railroad rolling stock. Alaska ( Аляска Alyaska) is a state in the United States of America, in the northwest of the North American continent [2]
Because of the lengths of trains and the high power requirements, HEP is supplied, in North America, as three-phase AC at 480-V (standard in the US and for Canada's VIA), 575-V (GO Transit, Toronto), or rarely 600-V. This article deals with where how and why "three phase" is used The volt (symbol V) is the SI derived unit of electric Potential difference or Electromotive force. VIA Rail Canada (also referred to as VIA Rail and VIA; ˈviːə 'vee-ah' is an independent Crown corporation offering intercity passenger rail GO Transit is the interregional public transit system serving the Conurbation in Ontario, Canada referred to by Metrolinx as the Transformers are fitted in each car for reduction to lower voltages. A transformer is a device that transfers Electrical energy from one circuit to another through inductively coupled Electrical conductors [3]
In the UK, ETS is supplied at 800-V to 1000-V AC/DC two pole (400 or 600-A), 1500-V AC two pole (800-A) or at 415-V 3 phase on the HST
References
External links
- Northwest Rail HEP products
- Stadco rail gens
- ANSI HEP recommended practice
- ANSI Recommended Practice for Head End Power Source Characteristics
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