MILW class EP-3
| MILW class EP-3 | |
|---|---|
 |
|
| Numbering: | 10300-10309 E10-E19 |
| Number: | 10 |
| Manufacturer: | Baldwin Locomotive Works , Westinghouse |
| Year of construction (s): | 1919 |
| Retirement: | 1952-1957 |
| Axis formula : | (2′Co1 ′) (1′Co2 ′) |
| Gauge : | 1435 mm ( standard gauge ) |
| Length: | 27.00 m |
| Height: | 4.42 m |
| Service mass: | 272 t |
| Friction mass: | 171 t |
| Top speed: | 105 km / h |
| Hourly output : | 3490 kW |
| Continuous output : | 2532 kW |
| Hourly traction: | 467 kN |
| Driving wheel diameter: | 1727 mm |
| Impeller diameter: | 914 mm |
| Power system : | 3000 V DC |
| Power transmission: | Overhead line |
| Number of traction motors: | 6th |
| Drive: | Westinghouse spring drive |
| Train heating: | Steam generator |
The EP-3 class of the Chicago, Milwaukee, St. Paul and Pacific Railroad ( Milwaukee Road ) is an electric locomotive developed by Baldwin Locomotive Works and Westinghouse for passenger traffic in the Cascade Mountains . Although they had good driving characteristics and were popular with the train drivers, the entire period of use was characterized by technical problems. They were among the first Milwaukee Road electric locomotives to be retired.
draft
When Milwaukee Road decided to electrify its Coast Division in 1917 , it intended to purchase locomotives from General Electric . However, the United States Railroad Administration (USRA) ordered that the order for electric locomotives should be split between General Electric and Westinghouse Electric. As a result, five of the 15 vehicles procured were in the form of the EP-2 "Bi-Polars" from General Electric and ten - namely the EP-3 series - from Westinghouse.
The EP-3 locomotives, which were designed for the same requirements as those for the EP-2, differed significantly from the siblings of General Electric. The appearance was smoother and less distinctive. The entire electrical equipment was again housed in a square box ( boxcab ), which, however, was not as pronounced as in the EP-1 . The axle arrangement in the two chassis, each with three 68- inch high driving wheelsets, corresponded to that of the Pacific design in steam locomotive construction and met the requirements for higher travel speeds.
The most notable aspect of the design was the engine structure. The six 566 hp double traction motors were flanged directly to the main frame above the drive axles. They each drove them via a hollow shaft drive , in which a 15-inch steel tube encircled the wheel axle and was connected to the wheel discs at the ends by steel springs. The drive motors set the hollow shaft in rotation via a gear drive. This structure significantly reduced the impacts on the wheel sets from the otherwise unsprung weight of the engine, and also spared the superstructure. The only non-sprung parts of the chassis were the wheelsets themselves. This type of construction was later also used prominently in the PRR class GG1 .
Construction errors and remodeling
The vehicles called Quills - hollow shafts went into operation between late 1919 and early 1921 and were given the road numbers 10300 to 10309. They were mainly assigned to the Mountain Division and quickly became very popular with the train drivers. They could easily pull trains up to 128 km / h even above the formal speed limit. They didn't have the tendency to skid like the boxcabs from the first generation and were much smoother than the Bi-Polars.
However, within a year some serious design flaws became apparent. Outwardly, the locomotives were identical to the New Haven EP2 , but heavier and therefore provided with a weaker frame. In contrast to the siblings on the east coast, the Milwaukee locomotives were always affected by broken axles and frame parts, cracked wheels and spokes, and bent suspension springs. This was an embarrassment for Westinghouse, who had made the machines too light and too rigid. There was insufficient lateral play in the engines, which led to severe wheel wear, and the frames broke under the heavy loads during the brisk journeys through the mountains.
In 1922, measures for constructive improvements were discussed. The company Baldwin , who had supplied the mechanical part, recommended dividing the frame into two parts, which practically a double locomotive would have led. The Milwaukee Road's Electrification Department under Reinier Beeuwkes came to a different conclusion and refused to recommend converting all ten machines into double locomotives. Instead, only number 10301 was modified accordingly, but for lack of success it was dismantled to a single-frame locomotive. It was only after the conversion of a second locomotive that successes became apparent: the entire series was converted for operation with just one driver's cab and equipped with a new running axle guide that kept the machines better in the curves. The frames were also rebuilt with thicker cross-sections.
Retirement
The locomotives never achieved the standards that were largely set by their sibling General Electric locomotives. They regularly caused headaches for the technical departments of Milwaukee Road and were rebuilt five times during their service life. They were prone to derailment and their weight exacerbated their consequences. One of the locomotives renumbered E10 – E19 in 1939, the E13, was destroyed in a derailment in Soudan (Montana) in 1947. When the class EP-4 “Little Joe” went into operation in the late 1940s and the older locomotives were worn out from intensive use during the Second World War, the department responsible for electrical operation planned to modernize the old electric locomotives. The EP-3 series was not included in the program. Instead, the seven remaining locomotives were gradually decommissioned and scrapped between 1952 and 1957, as the following table illustrates:
| numbering | Numbering 1939 | Serial number at Baldwin | construction | Retirement |
|---|---|---|---|---|
| 10300 | E10 | 51000 | December 1918 | Scrapped in May 1955 |
| 10301 | E11 | 51844 | June 1919 | Scrapped in April 1957 |
| 10302 | E12 | 51845 | June 1919 | Scrapped in May 1954 |
| 10303 | E19 (assigned but never used) | 52111 | August 1919 | Accident in January 1933; parked until it was scrapped in September 1942 |
| 10304 | E13 | 52170 | August 1919 | Accident in Soudan (Montana) , scrapped in July 1947 |
| 10305 | E14 | 52215 | August 1919 | Scrapped in September 1952 |
| 10306 | E15 | 52239 | August 1919 | Scrapped in May 1955 |
| 10307 | E16 | 52302 | September 1919 | Scrapped in May 1955 |
| 10308 | E17 | 52347 | September 1919 | Scrapped in December 1950 |
| 10309 | E18 | 52362 | September 1919 | Scrapped in April 1957 |
literature
- William D. Edson: Milwaukee Road All Time Steam, Diesel and Electric Roster . In: The Railway and Locomotive Historical Society Inc. (Ed.): Railroad History . No. 136, pp. 29-124.
- Noel T. Holley: The Milwaukee Electrics . Hundman Publishing Company, Edmonds (Washington) 1999.
- William D. Middleton: When the Steam Railroads Electrified . Kalmbach Publishing Company, Milwaukee (Wisconsin) 1974.
- Paul T. Warner: Locomotives of the Milwaukee Road . In: Southern California Chapter, Railway and Locomotive Historical Society (Eds.): Pacific Railway Journal . 2, No. 6, June 1958, pp. 3-55.
