Challenger (locomotive)
As locomotives of type Challenger are heavy four-cylinder - freight train steam locomotives with the wheel arrangement (2 'C) C2' (American spelling: 4-6-6-4), so with a leading two-axle drive bogie and three coupled axles (both axis groups in a laterally swiveling frame), three further coupling axles mounted in the main frame and finally a two-axle towing frame. Locomotives of this type were only used in the USA. Because of the simple steam expansion, these locomotives did not correspond to the Mallet design despite the external similarity like most American articulated locomotives .
origin of the name
The wheel arrangement was first used by the Union Pacific Railroad in 1936 for the 3900 class . This gave the locomotives the name "Challenger", which also became known as the wheel arrangement.
Delivered designs and use
Other railway companies also ordered locomotives with "Challenger" axles. However, due to the requirements, these differed from the model at Union Pacifis. The "Challenger" locomotives were built by the ALCO and Baldwin locomotive factories . A total of 252 locomotives of this type were produced. The UP class 3900 accounted for 105 copies.
The drive and coupling wheels had a diameter of 1750 or 1780 mm, the cylinder diameter varied between 520 and 580 millimeters with a piston stroke of 810 millimeters. The total mass of the locomotives was between 257 tons and 292 tons (excluding the tender ). The grate area had a size of 10 to 14 m². The larger grate area was needed by the locomotives of the Northern Pacific and the Spokane, Portland & Seattle, as they burned poorer coal.
In later versions the horizontal mobility of the front bogie was omitted. The necessary compensatory movements were only absorbed by the suspension, as it was possible to achieve a better mass balance and a more stable construction.
The Clinchfield Railroad needed at the beginning of World War II quick and powerful locomotives to meet the transport volume. She therefore ordered eight "Challenger" in the version of the Delaware & Hudson locomotives.
On the Delaware and Hudson Railway , the locomotives were used for fast freight traffic on the thoroughfare from Binghamton (New York) and Wilkes-Barre to Canada and on the Boston and Maine Railroad to Mechanicville .
The "Challenger" were also used in fast freight traffic on the Denver and Rio Grande Western Railroad . Here it was used on the route between Grand Junction (Colorado) and Salt Lake City . In 1943, more locomotives were required due to the higher transport volume caused by the war. However, since these could not be delivered by Baldwin as requested, D & RGW received six locomotives from a UP order from ALCO. However, the company did not buy the locomotives, but rented them from the Defense Plant Corporation. In 1947 the locomotives were no longer needed and passed on to the Clinchfield Railroad .
For the period from November 1937 to 1946 (No. 4000) and 1950 (No. 4001), the SP&S locomotives No. 903 and 904 were given to the Great Northern Railway to compensate for mileage.
Around the same time as the UP, the Northern Pacific Railroad needed a large, fast freight locomotive. The NP “Challenger” were created on the basis of the UP draft. They received cylinders with a diameter of 580 mm and a grate surface that was 40% larger than the UP locomotives. For testing purposes, No. 5104-5111 were fitted with Timken Company roller bearings . Despite the success of the tests, the NP was not convinced whether the roller bearings could withstand the requirements of freight transport. It was only when the previous plain bearings constantly caused problems that they were replaced by roller bearings. The types Z-7 and Z-8 had coupled wheel sets with a 1780 mm running circle diameter, closed driver's cabs and ten-axle tenders. The Z-8s were the last steam locomotives purchased by Northern Pacifics.
As part of the renewal of the vehicle fleet of the Spokane, Portland and Seattle Railway , the company received in 1937 with the NP version the identical "Challenger". However, they did have oil firing. In order to cope with the increased transport volume caused by the outbreak of the Second World War, two more locomotives were ordered. The last steam locomotive run on the SP&S network was No. 910 on June 23, 1956.
In order to cope with the increased transport volume at the end of the 1930s , the Western Maryland Railway procured 12 "Challenger". However, they turned out to be unsuitable for the rail company's circumstances, so that they were used most of the time in the towing and pushing service.
The seven “Challenger” procured by the Western Pacific Railroad were coal-fired and were used on the Elko (Nevada) - Salt Lake City route.
| society | designation | number | number | Manufacturer | Construction year | Retirement | comment |
|---|---|---|---|---|---|---|---|
| UP | CSA-1 | 3900-3914 | 15th | ALCO | 1936 | 1956-1952 | umgez. to 3800-3814 |
| UP | CSA-2 | 3915-3939 | 25th | ALCO | 1937 | 1956-1961 | umgez. to 3815-3839 |
| UP | 4664-5 | 3930-3949 | 20th | ALCO | 1944 | 1952-1960 | |
| UP | 4664-3 | 3950-3969 | 20th | ALCO | 1942 | 1958-1961 | |
| UP | 4664-4 | 3975-3999 | 25th | ALCO | 1936 | 1959-1961 | 3975-3984 rev. to 3708-3717 |
| Clinchfield | E-1 | 650-657 | 8th | ALCO | 1942-1943 | 1954 | |
| Clinchfield | E-2 | 660-663 | 4th | ALCO | 1947 | 1954 | |
| Clinchfield | E-3 | 670-675 | 6th | ALCO | 1943 | 1953 | Purchased by D & RGW in 1947 |
| D&H | J | 1500-1539 | 40 | ALCO | 1940-1946 | 1952-1953 | |
| D & RGW | L-97 | 3800-3805 | 6th | ALCO | 1943 | Sold to Clinchfield in 1947 | |
| D & RGW | L-105 | 3700-3709 | 10 | Baldwin | 1938 | 1951-1956 | |
| D & RGW | L-105 | 3710-3714 | 5 | Baldwin | 1942 | 1951-1956 | |
| GN | Z-6 | 4000, 4001 | 2 | ALCO | 1937 | SP&S 903 and 904, between 1937 and 1950 at GN |
|
| NP | Z-6 | 5100-5120 | 21st | ALCO | 1936-1937 | ||
| NP | Z-7 | 5121-5126 | 6th | ALCO | 1941 | ||
| NP | Z-8 | 5130-5149 | 20th | ALCO | 1943-1944 | ||
| SP&S | Z-6 | 900-905 | 6th | ALCO | 1937 | 1960 | identical to NP Z-6 |
| SP&S | Z-8 | 910, 9111 | 2 | ALCO | 1944 | 1960 | identical to NP Z-8 |
| WM | M-2 | 1201-1212 | 12 | Baldwin | 1940-1941 | 1952-1953 | |
| WP | M-100 | 401-407 | 7th | ALCO | 1938 | 1952 |
Whereabouts
Two "Challenger" locomotives have been preserved: Union Pacific No. 3985 is the largest operational steam locomotive in the world and performs special trips; 3977 (converted to oil firing in 1952 and renumbered 3710) is a technical monument in a park in North Platte , Nebraska.
