Amtrak Head End Power (HEP) Program
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This page was last updated on April 28, 2019.
Amtrak uses three-phase AC at 480 volts 60 Hz for its head-end power, which is the standard in the US. Head end power is provided for all heating, cooling, and lighting electrical loads. Each car is equipped with cabling and connectors (four at each end) capable of passing 1,200 kW (1.2mW) of power, at 400 amps, along the entire train, regardless of the car's position in the train.
For cars owned by Amtrak, and for cars not owned by Amtrak that may travel as part of an Amtrak train, each car must be able to carry the full electrical load of the train, regardless of the car's position in the train. Each car must have compatible electrical plugs and sockets at each end. These connectors (plugs and sockets) are designed to transmit power from one car to the next. To accomplish this, each car has a plug and receptacle on each side of each end, for a total of four plugs and four receptacles. In this manner, the load is actually split among the four sets of cables and the car is part of the electrical circuit for the entire train. To complete the circuit, the last car at each end of the train has its plug on one side connected to the receptacle on the other side.
Amtrak's HEP uses 480V AC, at about 200 Amps and 96kW, which Amtrak limits to 85kW per car. This standard limits train size to about 15 cars, based on Amtrak's limit of 1,200kW per train. VIA in Canada also uses 480V, but a different wiring diagram, meaning that the connectors and HEP systems are not compatible without adapters. (GO Transit, a commuter railroad serving the Greater Toronto and Hamilton Area uses 575V. GO Transit was Canada's first commuter rail network, and was started by the Provincial government of Ontario in 1967.)
The two Head End Power systems in use today depend on either the 480V standard industrial U.S. voltage, or the 575V standard industrial Canadian voltage. The 575V standard for HEP was previously used by CN for their Tempo cars, built by Hawker-Sniddley Canada in 1968, along with the more modern Bombardier BiLevel Coach, developed in Canada for GO Transit, and initially built by Hawker-Sniddley Canada and delivered in March 1977.
The 480V HEP connector and receptacle design is documented in Amtrak Drawing D-12-7191, and the system specification is Amtrak's D-77-24. The connector is known as a break-away style, which was first used on Amtrak's Amfleet cars.
Almost all of the cars acquired by Amtrak beginning in 1971 were steam-heated and had their own axle-driven generators. The arrival of 492 Amfleet cars between 1975 and 1977 began the wholesale change to HEP and allowed Amtrak to begin retiring older cars, especially coaches. While Amfleet cars came in several different interior configurations, most were 84-seat coaches intended for short- and medium-distance service, and none of them originally included sleeping accommodations.
In July 1973, Amtrak took delivery of the first of 40 new SDP40F locomotives from Electro-Motive, meant to replace 74 ex AT&SF F-units. The new locomotives were equipped with two steam generators, with the capability for later installation of two 375-kilowatt auxiliary diesel generators to furnish the planned 480-volt three-phase A.C. electrical system.
In 1975, Amtrak started to take delivery of the all-electric Amfleet car, hauled by General Electric (GE) P30CH and, later, EMD F40PH locomotives, both unit types being equipped to furnish HEP. Following the introduction of the Amfleet fleet, the (also all-electric) Superliner railcar was placed into operation for servicing long-distance western routes. Amtrak subsequently converted a portion of the steam heated fleet to all-electric operation using HEP, and retired the remaining unconverted cars.
In 1976 Amtrak rebuilt 30 former U.S. Army kitchen cars into baggage cars 1350-1379, which could be used on either steam-heated or HEP trains.
Severe weather in January 1977 resulted in many steam-heated cars being bad-ordered with freeze damage. As a result of this equipment shortage, several medium- and long-distance trains such as the City of New Orleans were temporarily discontinued while Amtrak rearranged its fleet. After a few weeks, these trains were reinstated with 1350-series baggage cars and Amfleet coaches and food-service cars; but no sleepers. This was certainly not a good situation for long-distance overnight trains.
In 1977, following the delivery of their new Amfleet cars in 1975 and 1976, and new F40PH locomotives also in 1976, Amtrak began a program to rebuild its fleet of previously railroad-owned passenger cars from being steam-heated cars, to electric-power, known as head end power, or HEP. The work was done at Amtrak's Beech Grove shops, near Indianapolis, Indiana, and the program lasted through the mid 1980s, with only about one-third of the fleet being completed. Cars were selected for HEP conversion as other repair work was needed, with an emphasis placed on Budd-built cars in a few standard configurations, although many of the newest ex-UP non-Budd cars were included. After completion, most of the HEP cars were renumbered into a new number series. At about the same time, Amtrak designated its previously railroad-owned passenger cars, rebuilt or not, as its Heritage fleet. The previously railroad-owned cars were commonly known as "conventional" cars. The dome cars were added to the HEP program later on, and about 20 sleepers that were assigned HEP numbers were never rebuilt with electric power.
With an immediate need for HEP sleepers, Amtrak began converting 25 cars in May 1977. The program initially involved some of the former Union Pacific "Pacific"-series 10-roomette/6-double-bedroom cars, as these were considered some of Amtrak's best sleepers. They had been well-maintained by the UP, and were stainless steel with good insulation, outside-swing-hanger trucks and disk brakes. They also had relatively reliable electro-mechanical air conditioning, which would be replaced during the conversion to HEP. These cars retained their former names, but were renumbered from the 2600-series into the 2900-series, keeping the same last two digits.
After 13 of the Pacific cars had been rebuilt, Amtrak decided to renumber the additional HEP sleepers into a contiguous block as they came out of the shop. It also decided to concentrate on the former Santa Fe "Pine"-series sleepers instead of the UP Pacific cars. The Pine cars had been built at the same time as the Pacific cars and they were very similar inside and out; but the Pine cars had relatively unreliable and difficult-to-maintain steam ejector air conditioning, so it made more sense to convert these cars ahead of the Pacific cars, with their better air conditioning.
In addition to the sleeper conversions, Amtrak began modifying additional baggage cars so they could run on both steam-heated and HEP trains. During 1977-78, seventy former Santa Fe cars were converted and renumbered: 1203-1249 had been built by Budd in 1953 and 1957 while the 1250-1272 had been constructed by ACF in 1950 and 1955.
Amtrak's Heritage Fleet program was started in 1977 to equip older cars from Amtrak's predecessor railroads to Head End Power. These conversions were performed at Amtrak's heavy repair center in Beech Grove, Indiana, outside of Indianapolis. The program was completed by the mid 1980's.
The delivery of 284 Superliner cars between 1979 and 1981 allowed Amtrak to reequip all of its western long-distance trains and to continue retiring older cars. As the first Superliners were arriving, Amtrak began a major, multi-year program to rebuild various types of cars for HEP operation on long-distance trains throughout the east, and this is when it adopted the Heritage Fleet name for all of the rebuilt cars. Amtrak's preference for the HEP program was stainless steel cars, and about 70 per cent of the cars rebuilt for HEP operation had been constructed by Budd.
The arrival of 150 Amfleet II long-distance cars in 1981-1983 permitted the retirement of even more of the old equipment, and the conversion of the Silver Star to HEP in March 1982 made Amtrak an all-HEP railroad.
The following comes from "Amtrak By The Numbers" page 170:
Head-End Power, or "HEP" allowed Amtrak to phase out the antiquated practice of heating its passenger cars with steam. Instead, car functions such as lighting, climate control, and food refrigeration and cooking were powered by electricity supplied by the locomotive or, in some instances, a dedicated power car.
Amtrak's first new cars built new with HEP capability debuted in 1975 with Amfleet, and within a few years the decision had been made to rebuild hundreds of mechanically sound "original purchase" cars as the Heritage Fleet, with their former steam-heat components replaced with HEP connections.
The Heritage Fleet originated when 30 former U.S. Army kitchen cars were converted to baggage cars for use with the new Amfleet equipment. Amtrak had by then converted most Northeast Corridor trains to Amfleet, but the overnight Boston-Washington, D.C., train was operating as a hybrid consist with a steam-heated baggage car and sleepers, HEP Amfleet cars and a power car. (A number of baggage cars had been converted to power cars to allow GG-ls and steam-generator-equipped E60s to pull the new Amfleet cars). To simplify matters, four sleepers with a roomette-bedroom configuration were converted to HEP. Moreover, a small number of former U.S. Army ambulance cars also received the HEP upgrade. This permitted the conversion of the National Limited and Montrealer to Amfleet equipment.
Meanwhile, a number of contract shops had been busy overhauling most of the "original purchase" cars that Amtrak planned to retain, so that by the time of company's five-year anniversary in the spring of 1976, most of these cars had received their Amtrak styling and assigned numbers. Most of the fleet was still steam-heated, however.
Since many of the cars were deemed to be in relatively good condition, and anticipating the "arrival" of displaced equipment from Western trains re-equipped with Superliners, Amtrak embarked on a program that would convert them to HEP. Beginning with the Lake Shore Limited in October 1979 and finishing up with the last set of Silver Star cars in March 1983, the Broadway, Crescent, and Silver Meteor also were upgraded to Heritage cars. (The Southern Railway, initially a holdout, had joined Amtrak in 1979; Rio Grande would follow four years later).
All through this period, hundreds of retired cars were disposed of through equipment sales. The best were not released until the early 1990s, when some of the last cars were sold from storage to VIA Rail Canada to augment that company's own HEP conversion program.
Amtrak's planned Heritage conversions were curtailed somewhat by the 1981 arrival of the first Amfleet-II cars, which included 125 coaches and 25 lounge cars. These were similar to their earlier Amfleet-I siblings, but sported larger windows, different trucks, and a single vestibule.
Amtrak reached into its stored stockpile for the last time to any major extent when it refurbished cars to replace the erstwhile privately owned Auto-Train in 1983-84.
Most Amtrak baggage cars were numbered in the 1100-1300 series after HEP conversion. Baggage-dorms were numbered in the 1600 series, and "Specialty Baggage" cars, generally rebuilt from HEP coaches for extra mail-handling capability in the mid-1990s, were numbered in the 1700 and 1800 series.
Slumbercoaches were numbered in the 2000 series, and all-bedroom cars were placed in the 2200 series. Cars of the most common sleeper configuration, 10-6, received numbers in the 2400, 2800, and 2900 series. Following the delivery of Viewliner sleepers, 25 Heritage 10-6 sleepers were converted to sleeper-dorms in the 2500 series.
All configurations of Heritage Fleet lounge cars were numbered in the 3100 series.
As with the original steam-heated numbering, the first two digits of coach numbers indicated how many revenue seats the car contained. Cars for long-distance service—with legrests—were in the 4000, 4600, and 4700 series. Short-haul, high-capacity cars (Clocker coaches, etc.) were placed in the 7000 and 7600 series.
All configurations of diners remained in the 8000 series following HEP conversion.
Dome-lounge cars received HEP numbers in the 9300 series (with the second digit-3—denoting lounge configuration), while dome coaches received numbers in the 9400 series.
Former Santa Fe Hi-Level cars received five-digit numbers in the 39900 series. The fourth digit was used to denote the type of car. Lounges were 3997x and diners were 3998x; all other HEP Hi-Level cars were coaches.
Amtrak's HEP-Equipped Cars (delivered new)
(Read more about Amtrak's cars equipped with HEP -- including Amfleet I and Amfleet II, Superliner I and Superliner II, Horizon fleet, and Viewliners)
Amtrak's HEP-Equipped Locomotives (delivered new)
(Read more about Amtrak's first locomotives -- including the SDP40Fs and the later locomotives equipped with HEP)
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Michael Palmieri provided the inital source material for this article, via emails dated November 9 and 10, 2011.