SJ class Dm

SJ class Dm

SJ class Dm

Designed to haul iron ore trains of weight in excess of 5000t over the 1 in 100 (1%) grades of the Lulea - Narvik corridor; the Dm3 was for many years the world's most powerful electric locomotive.

Based on the simple but succesful locomotive designs of the 1920's; the Class Dm ('m' for malm or iron) were virtually 2 single ended Class D units coupled back to back, and having one trailing axle on each replaced by coupled drivers.

Introduced in the 1940's, these double headed monsters began to work the tricky iron ore line; along with 4 units owned by the Norwegian State Railways (NSB class el 12). The popularity and survival of the Rod-Drive design at these lattitudes could perhaps be attributed to it's effectiveness as a method of controlling slip on individual pairs of wheels; amid the polar temperatures of the Arctic circle.

By 1960 it was apparent that greater power was required, and SJ opted for cabless units without pantographs, that were placed in service between the vehicles of Dm Class pairs. The resulting Dm3 Class developed a whopping output of 9,600hp. The high tractive effort of over 900kN resulted in excessive strain on standard screw couplers; and accordingly SJ embarked on a programme of replacing them with Russian pattern automatic couplers.

The data below is for the configuration Dm + Dm, (a.k.a. Dm2):

Company: Statens Järnvägar (SJ)
Model: Dm + Dm
Year: 1960
Propulsion: 15kV AC 16-2/3Hz; ASEA KJD 137
Traction Motors: 4 x 1200 kW (4800kW)
Starting Tractive Effort: 520kN
Continuous Tractive Effort: 250kN
Maximum Speed: 75 km/h
Axle arrangement: 1'D + D1'
Driving wheel diameter: 1540mm
Trailing wheel diameter: 990mm
Wheelbase: 21,370mm
Length: 25,100mm
Width: 3,370mm
Height (over lowered pantograph): 4,500mm
Weight: 190.0t

Author: Mats Strid

SJ class Dm
• config.txt 5.85KB
sj_dm_alpha_numbers
alphanumber_0a.tga 4.04KB
alphanumber_0b.tga 4.04KB
alphanumber_1a.tga 4.04KB
alphanumber_1b.tga 4.04KB
alphanumber_2a.tga 4.04KB
alphanumber_2b.tga 4.04KB
alphanumber_3a.tga 4.04KB
alphanumber_3b.tga 4.04KB
alphanumber_4a.tga 4.04KB
alphanumber_4b.tga 4.04KB
alphanumber_5a.tga 4.04KB
alphanumber_5b.tga 4.04KB
alphanumber_6a.tga 4.04KB
alphanumber_6b.tga 4.04KB
alphanumber_7a.tga 4.04KB
alphanumber_7b.tga 4.04KB
alphanumber_8a.tga 4.04KB
alphanumber_8b.tga 4.04KB
alphanumber_9a.tga 4.04KB
alphanumber_9b.tga 4.04KB
sj_dm_art
sj_dm_art_512.texture 1.33MB
sj_dm_art_icon.texture 42.81KB
sj_dm_body
comb.texture 21.46KB
digit_4a.texture 5.46KB
digit_4b.texture 5.46KB
digit_5a.texture 5.46KB
digit_5b.texture 5.46KB
digit_6a.texture 5.46KB
digit_6b.texture 5.46KB
dm.texture 5.33MB
frame.texture 85.47KB
reflect.texture 21.46KB
sj_dm_body.pm 312.72KB
sj_dm_shadow
black.texture 1.45KB
sj_dm_shadow.pm 28.44KB