 Two mainline Bo'Bo' locomotives were delivered by Siemens-Schukert in 1935, which were named "Oscar" and "Ivar".They were followed by the Bo "Laila" and "Gerd" two years later—which could operate both on the mainline and at the port.During the late 1930s, the railway company started replacing the rails with heavier 35 kilograms per meter (70 lb/yd) rails, although this work was not completed.