"These were popular trains that people used and needed," said leader Nooshi Dadgostar at a press conference at Stockholm Central Station, as Sweden's election campaign kicks off in earnest.
The party also wants to secure long-term state funding for the night trains.
The Left Party points to many popular routes being discontinued, including night train service from Gothenburg to Umeå and to Jämtland, which were stopped in 2025.
The Left Party also said it wants to accelerate work on the double track along the East Coast Line, from Gävle to Härnösand.
"It is one of the most important routes to tie the country together," said Dadgostar.
She wants the entire double track section to be completed by 2035.