And the Swedes did not attack German train transports because the traffic was according to a pass-through agreement.
USSR and Germany forced these pass-through agreements after Winter War. USSR was in pact with Germany, and both acquired permission to transit troops to their bases, Soviets to Hanko (Hangö) that it took in Winter War, and Germany to northern Norway which it took in April-June 1940. Sweden was surrounded from three sides by Germany, and in the fourth side was Finland badly weakened by Soviets attacking, with increasing Soviet pressure also after Winter War.
USSR and Germany forced these pass-through agreements after Winter War. USSR was in pact with Germany, and both acquired permission to transit troops to their bases, Soviets to Hanko (Hangö) that it took in Winter War, and Germany to northern Norway which it took in April-June 1940. Sweden was surrounded from three sides by Germany, and in the fourth side was Finland badly weakened by Soviets attacking, with increasing Soviet pressure also after Winter War.