dv12 number 2501 was modified between 1978 and 1980 to run on electricity instead of diesel, becoming class sv1 number 3201. the locomotive was used first in freight traffic, later in passenger trains between helsinki and imatra. the sv1 was used to test three-phase alternating current electrical engines; the results were used when developing class dr16. the electrical components were delivered by strömberg, which was also involved in the dr16 project. the locomotive was painted yellow with black stripes, a colour scheme known from another short-lived prototype, the dr15.