NSB Di 4
| Company type | Diesel-electric locomotive |
|---|---|
| Industry | Rail transport |
| Founded | 1981 |
| Founder | Henschel, Brown, Boveri & Cie, General Motors Electro-Motive Division |
| Headquarters | Norway |
| Products | Diesel-electric locomotives |
NSB Di 4 Overview
NSB Di 4 refers to a fleet of five diesel-electric locomotives constructed by Henschel for the Norwegian State Railways (NSB). These units, introduced in 1981, primarily serve passenger trains along the Nordland Line and, since 2001, have remained NSB’s sole diesel locomotives in commercial operation. Their electrical systems were supplied by Brown, Boveri & Cie, while propulsion is provided by a General Motors Electro-Motive Division 16-645E prime mover. This configuration delivers a power output of approximately 2,450 kilowatts (3,290 hp) and an initial tractive effort rated at 360 kilonewtons (81,000 lbf).
Commissioned in the late 1970s to complement and eventually succeed the Di 3 class, the Di 4 shares technical characteristics with Denmark’s DSB Class ME. Initially, there were plans for design commonality with NSB’s electric El 17 locomotives; however, this concept was ultimately abandoned. Notably, the Di 4 holds the distinction of being the first asynchronous locomotive deployed in revenue service worldwide. Although a follow-up order for additional units was considered for delivery during the 1980s, it never materialized.
History
Throughout the 1950s and 1960s, NSB received a total of thirty-five Di 3 locomotives. Although plans during the 1960s included placing further orders for Di 3 units in the early 1970s, these plans were ultimately abandoned. Instead, NSB initiated the development of a new locomotive class.[1] The manufacturing was carried out by Henschel, based in Kassel, Germany. Electrical systems were supplied by Brown, Boveri & Cie from Mannheim, Germany, while the engine-generator was sourced from General Motors.[2] The Di 4 shares technical similarities with the Class ME locomotives acquired by DSB in Denmark.[3] Notably, the Di 4 was NSB’s first locomotive equipped with three-phase and asynchronous motor technology,[4] marking it as the world’s inaugural asynchronous locomotive to enter commercial service.[5] Henschel was simultaneously producing the NSB El 17, and there were initial plans for both models to utilize identical traction motors and rectifiers to maximize component commonality. However, this idea was discarded because the components intended for the Di 4 were too heavy for use in the El 17.[6]
The five Di 4 locomotives were delivered in 1981 and frequently operated in multiple with Di 3 units.[1] Due to its greater axle load compared to the Di 3, the Di 4 was restricted from operating north of Mo i Rana on the Nordland Line from the outset.[7] By 1987, NSB contemplated ordering additional Di 4 units with deliveries planned for 1989 and 1990; however, this order never materialized.[7] The intended batch would have included six to ten locomotives featuring an updated ventilation system and a more powerful engine.[2] As time passed, NSB shifted focus towards acquiring a more modern class and placed an order for twelve Di 6 locomotives in 1992.[8] Unfortunately, the Di 6 proved unreliable and was ultimately returned to its manufacturer.[9] Following the withdrawal of the Di 3 fleet in 2001, the Di 4 remains NSB’s sole diesel locomotive class in revenue service.[10]
On 24 October 2024, Di 4 unit number 4.653 was involved in a fatal derailment on the Nordland Line while hauling a passenger train between Bjerka and Mo i Rana along a section parallel to the E6 highway. Preliminary findings indicate that a rockfall caused the derailment. The train driver lost their life in the accident, and four passengers sustained injuries.[11][12]
Specifications
These locomotives are powered by a General Motors Electro-Motive Division V16 16-645E3B prime mover, paired with an EMD AR7-D14B generator, delivering a maximum power output of 2,450 kilowatts (3,290 hp) at 900 revolutions per minute. Each cylinder of the prime mover has a displacement of 10.570 litres (645.0 cu in), featuring a bore diameter of 230.2 millimeters (9.06 in) and a piston stroke length of 254 millimeters (10.0 in). This setup generates a starting tractive effort rated at 360 kilonewtons (81,000 lbf). The wheel configuration follows a Co′Co′ arrangement, equipped with six QD 335N4A traction motors manufactured by Norsk Elektrisk & Brown Boveri.[1]
The distance between the outer and middle axles measures 1.850 meters (6 ft 0.8 in), while the spacing between the middle and inner axles is 2.000 meters (6 ft 6.7 in). The total length between the outermost axles spans 15.600 meters (51 ft 2.2 in). Each axle supports a load of approximately 19.1 tonnes (18.8 long tons; 21.1 short tons). The overall length of the locomotive is 20.800 meters (68 ft 2.9 in), with a height reaching 4.350 meters (14 ft 3.3 in).[3] When new, the wheel diameter measures 1,100 millimeters (43 in).[2]
- ↑ 1.0 1.1 1.2 Næss, p. 54.
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- ↑ Hartmark, p. 24.
- ↑ Aspenberg, p. 119.
- ↑ 7.0 7.1 Næss, p. 72.
- ↑ Næss, p. 100.
- ↑ Næss, p. 139.
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