UP class 4000

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UP class 4000 "Big Boy"
Big Boy 4019 in Echo Canyon, Utah
Big Boy 4019 in Echo Canyon, Utah
Numbering: 4000-4024
Number: 25th
Manufacturer: ALCO
Year of construction (s): 1941, 1944
Axis formula : (2'D) D2 'h4
Gauge : 1435 mm (4 ft 8½ in)
Length over coupling: 40,500 mm
Height: 4940 mm
Width: 3400 mm
Service mass: 350.2 t
Service mass with tender: 548.3 t
Friction mass: 247.2 t
Wheel set mass : approx. 31 t
Top speed: 112 km / h (70 mph)
Indexed performance : 6290 hp (4560 kW)
Starting tractive effort: 602 kN
Driving wheel diameter: 1727.2 mm
Impeller diameter front: 914.4 mm
Rear wheel diameter: 1066.8 mm
Control type : Walschaerts
Number of cylinders: 4th
Cylinder diameter: 603 mm
Piston stroke: 813 mm
Boiler overpressure: 21.1 bar
Grate area: 13.97 m²
Superheater area : 229 m²
Evaporation heating surface: 547 m²
Tender: Centipede
Service weight of the tender: 198.1 t
Water supply: 94.6 m³
Fuel supply: 25.4 tons of coal

The class 4000 of the Union Pacific Railroad (UP), known as Big Boy , is the largest and most powerful steam locomotive class of UP and one of the largest and most powerful in the world.

A total of 25 units of the type were built by the American Locomotive Company (ALCO), 20 in 1941 and five in 1944. The machine was designed by a team led by Otto Jabelmann, who was also responsible for the predecessor class, which was also built in parallel 3900 (manufacturer's designation Challenger with the wheel arrangement (2'C) C2 '. The designation Big Boy , which he wrote in chalk on the smoke chamber , comes from an unknown employee of the ALCO works . The designation quickly became popular for the locomotives of the UP class 4000.

Construction and technology

The locomotives were specially designed by the Union Pacific Railroad for use in front of freight trains in the Rocky Mountains in order to avoid the labor-intensive use of leader and push locomotives on the inclines across the continental divide . The most difficult section on the transcontinental route of the Union Pacific was a long slope over Sherman Hill in Albany County (Wyoming) south of the Ames Monument with a max. Incline of 15.5 ‰. The new locomotives should bring trains with 3600 short tons (about 3300 t) without a leader or push locomotive over this incline, but also be fast enough to be able to travel the entire route between Cheyenne (Wyoming) and Ogden (Utah) without changing locomotives.

The required performance data resulted in an articulated locomotive with the wheel arrangement (2'D) D2 'h4 ( Whyte notation : 4-8-8-4). No other locomotive has ever been built with this wheel arrangement. Like many of the newer American articulated locomotives, the Big Boys were not actually mallet locomotives , because the steam engines operated with simple steam expansion without a compound effect . In America, this design is therefore referred to as simple articulated (e.g. articulated locomotive with single expansion). The frames of both engines were integral cast frames including the cylinders, the towing axles are mounted in a cast Delta towing frame. The axle and rod bearings were roller bearings.

For firing with inferior coal , the fire box was designed to be very large with a grate surface of almost 14 m². The locomotives have a mechanical grate feed via a stoker . During an individually documented journey with a train mass of 3530 tons and a speed of 41.1 mph or 66 km / h , a consumption of 8.8 tons of coal per hour was determined. The locomotive 4005 was converted to the main oil firing on a trial basis , but this did not prove itself and therefore it was converted back to coal firing.

With a total mass of 548.3 t and a maximum continuous output of 6290 HP on the towing hook (at 48 km / h), the Series 4000 machines are among the heaviest and most powerful steam locomotives ever built and with a maximum permissible speed of 112 km / h (70 km / h) mph) is also one of the fastest articulated steam locomotives. The construction was even designed for 129 km / h (80 mph) in order to offer a high safety margin.

In order to be able to use the locomotives, the route between Ogden (Utah) and Green River (Wyoming) ( Overland Route ) had to be rebuilt in several places. Almost every curve was re-routed so that two 4000 series locomotives could meet. The superstructure was also reinforced.

Operational use

The Big Boys fully met the expectations placed on them. The main area of ​​application was the route over the Rocky Mountains from Wyoming to Utah : From Cheyenne (Wyoming) over the Sherman Hill Pass to Laramie (Wyoming) and on over Green River (Wyoming) , Evanston (Wyoming) and through the Echo Canyon ( Utah) to Ogden, Utah . In practice, they pulled trains of up to 6,000 tons, and in a test on the plain, one of these locomotives was even able to keep a 25,000-ton train running on its own, which had been pushed with other locomotives .

From 1941 to 1957, the locomotives were regularly used in freight traffic in front of freight trains. In the western and more demanding section of the route over the Wasatch Mountains between Ogden and Green River, the Big Boys were first replaced by the gas turbine locomotives of the Union Pacific Railroad . The stretch over Sherman Hill from Green River to Cheyenne remained. The last train hauled by a Big Boy ran in 1959. Each of the locomotives built in 1941 and 1944 covered a total of more than 1.6 million kilometers. Four locomotives were kept operational as a reserve until 1962.

Infrastructure

Before the locomotives could be used, extensive expansions to the infrastructure were necessary. In 1941, for example, the 100-foot turntables (30 m) in the Ogden (Utah) , Green River (Wyoming) and Laramie (Wyoming) sites were replaced by 135-foot (41 m) turntables.

The hub in Cheyenne, Wyoming , a little further east ( 41 ° 7 ′ 47.5 ″  N , 104 ° 48 ′ 54.8 ″  W ) with a length of 126 feet still exists today. It was installed in 1941 to replace a 100-foot disc. For the total axle distance of 117 ft 7 in (35.83 m), this was just enough to turn the locomotive with the overhang. Due to the risk of accidents for people and waiting locomotives as well as when stopping the locomotive, caution was required.

The stalls of the roundhouse in Cheyenne were too short for the locomotives, so that some had to be extended with stems. The main workshop in Cheyenne had the necessary facilities (cranes, machine tools, axle sink) to carry out major repairs on the machines.

Preserved copies

Overview

Locomotive 4014 in Pomona, California

Eight of the 25 Big Boys built have been preserved, currently (2019) only the 4014 is in working order:

Recommissioning of the UP 4014

The Union Pacific already operated the Challenger No. 3985 of the predecessor class 3900 as the largest operational steam locomotive in the world and for a long time it was of the opinion that the reconditioning and commissioning of a Big Boy was not worthwhile, because its area of ​​application was due to the small arc radii of many routes and the large one The overhang of the locomotive is very limited. The Challenger 3985 of the UP looks very similar to a class 4000 locomotive and also has the advantage of being oil- fired , while a Big Boy could be fired with coal.

On July 24, 2013, however, the UP announced in a press release that it had repurchased locomotive No. 4014 from the Southern California Chapter of the Railway & Locomotive Historical Society in Pomona, California. The machine was to be brought to the Union Pacific workshop in Cheyenne and worked there until 2019. During the refurbishment, the locomotive was converted to run on oil.

The 4014 locomotive had covered around 1.65 million km in twenty years of operation. It was shut down in December 1961.

In autumn 2013, the machine in Pomona was revised to such an extent that it could roll again. She was moved over a provisionally laid track in the parking lot of County Fairplex and then prepared for the transfer to Cheyenne in the Union Pacific marshalling yard in Colton . The locomotive arrived there on May 8, 2014 after a journey of several days.

As part of "The Great Race to Ogden", the 4014 left the Cheyenne Depot Museum on May 4, 2019, to arrive in Ogden on May 9, one day before the 150th anniversary of the completion of the first transcontinental rail link . On this anniversary she played a leading role.

The big boy in comparison

The back wall of locomotive 4017 in the National Railroad Museum in Green Bay

The Big Boy is widely regarded as the largest steam locomotive in the world. In fact, the design was outdone by other locomotives in all of the features that can be used for a size comparison, such as length, tractive effort, mass and power.

The longest steam locomotive with 49,225 mm was the class TE1 of the Norfolk and Western Railway , equipped with a steam turbine generator and electric single-axle drive in the wheel arrangement (Co'Co ') (Co'Co'). A similar locomotive of the Chesapeake & Ohio Railway , the class M-1 , was longer, and both locomotive types had a higher mass than the Big Boy. The longest steam locomotive with a piston steam engine was the PRR S1 with 42,700 mm.

The Big Boys were designed for routes that were approved for axle loads of “only” 31 tonnes, a rather average figure for US standards. Other locomotives, which were designed for higher axle loads and were fired with better coal, were able to outperform the UP class 4000. These included the roughly equally heavy class H-8 of the Chesapeake & Ohio Railway with 7500 hp (also measured on the drawbar) and the duplex locomotive Q2 of the Pennsylvania Railroad with 8000 hp (measured on the test bench).

Also worth mentioning is the Class A of the Norfolk and Western Railway with 6300 HP tow hook power , which was designed to be less powerful but faster than the locomotives of the UP series 4000. Among other things, because of good coal, the same performance could be achieved despite the significantly lower operating mass. According to Arnold Haas, this was as much as 6450 HP on the draw hook (at 70 km / h), whereby the locomotive could transport heavy express freight trains at 130 km / h.

In terms of tractive power, the Big Boys were clearly surpassed by the Triplex Mallets , which each had twelve driving axles in three groups, but could only achieve low speeds.

Locomotive 4023, side view

A few modern large steam locomotives also exceeded the Big Boys by a few percent in terms of tractive effort and friction mass , for example the M3 and M4 classes of the Duluth, Missabe and Iron Range Railway , which were also considered very successful, and which hauled the heaviest scheduled steam-driven trains in the world (in easy terrain) : a single locomotive moved ore trains from 15,500 to 17,500 tons at a speed of max. 48 km / h. In contrast to these machines , the Big Boys were usually traveling at 112 km / h after conquering the UP mountain route and, due to their good running properties, often even a little faster. An M3 or M4 developed 6250 hp on the towing hook, but would have been useless for this fast-freight service because of its far too low top speed .

Some railways preferred locomotives of much simpler construction with only one two-cylinder engine . Their largest representatives ( Texas ) achieved 90% of the draw hook performance of a Big Boy . However, high permissible axle loads and good fuel were a prerequisite for this and the machines did not achieve their high tractive power in the lower speed range. At medium speed, however , they were hardly inferior to the Big Boy and the most powerful types carried coal trains with 12,000 tons on flat terrain.

The ease of use of the Big Boys for train drivers and stokers was praised, which was important for the UP in World War II , since then often only semi-skilled assistants could be used as stokers on these fully utilized locomotives. Failures on the approx. 60 km long ascent, the bottleneck of the congested transcontinental route, would have been very obstructive.

Over time, a total of 105 units of the predecessor type UP 3900 had been procured by 1944, most of which were also in operation for longer.

swell

  • Linn H. Westcott (Ed.): Steam Locomotives . Model Railroader Cyclopedia, vol. 1. Second edition. Kalmbach, Milwaukee (USA) 1981. (1960)
  • Arnold Haas: Steam Locomotives in North America. USA and Canada. Franckh, Stuttgart 1978, ISBN 3-440-04493-9 .

Movie

Big Boy 4014 and 844 USA steam locomotives May 4, 2019
  • Union Pacific Railroad: Last of the Giants . Contemporary film about the series produced by the UP
  • SWR : Eisenbahn-Romantik - Big Boy (episode 433 of November 11, 2001), including the aforementioned film Last of the Giants
  • Pentrex: Big Boy 4014 Update . DVD about the transport of the Big Boy 4014 from the RailGiants Museum in Pomona across California
  • RailMedia: Big Boy 4014 returns home . DVD / Blu-ray about the transport of the 4014 over the former main route from Ogden to Cheyenne

Web links

Commons : UP class 4000  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ Union Pacific 4-8-8-4 “Bigboy” Locomotives of the USA
  2. ^ Railway gazette international, Volume 79, Reed Business Pub., 1943, p. 192.
  3. ^ Railway locomotives and cars, Volume 114, Simmons-Boardman Pub. Corp., 1940, p. 521.
  4. ↑ The Largest Turntable in the World? in: Railway Gazette International, Volume 84, Reed Business Pub., 1946, p. 507.
  5. ↑ The most famous route of Big Boy? , cs.trains.com, 06-21-2007 6:19 PM (with photo)
  6. ↑ Union Pacific press release of July 24, 2013, accessed September 20, 2013
  7. ↑ Union Pacific website on Locomotive No. 4014, accessed December 25, 2013
  8. ↑ Union Pacific website on Locomotive No. 4014, accessed December 25, 2013
  9. ↑ Union Pacific press release of November 14, 2013, accessed December 25, 2013
  10. ^ UP Steam website, accessed December 25, 2013
  11. ^ UP Steam website, accessed May 28, 2014
  12. ↑ https://www.youtube.com/watch?v=RR7Q27cIEvo
  13. ↑ https://www.up.com/heritage/steam/schedule/index.htm
  14. ^ The Norfolk & Western Info Page C-C + CC TE1