Transport Minister Lulu Ranne (Finns) says a long-delayed cross-border train to Sweden should begin rolling this summer, allowing passengers to ride the rails from continental Europe to Finnish Lapland, or overland between the Finnish and Swedish capitals.
Finland and Russia already use different rail gauge, because Finland still uses the older Russian (Empire) gauge and Russia uses “Soviet” gauge. Its only a 4 mm difference but still any trains that would have to run both gauges have to be designed for both, which most of russian trains are not.
Also the electrical system is completely different