MOSCOW- Russia is bringing in soldiers to increase rail capacity in its far east and make up for a shortage of migrant labour during the coronavirus pandemic.

As part of a more than 6 trillion rouble ($79 billion) plan to upgrade and construct nationwide infrastructure, Russia is expanding its Baikal-Amur Mainline railway (BAM) to transport more coal and metal cargo to ports for export to Asia.

But coronavirus restrictions have prompted many foreign migrant workers to leave Russia, and Deputy Construction Minister Nikita Stasishin warned last year that construction projects could be slowed down by a workforce deficit.

Railway troops, which protect, build and repair railways, will begin building a second line of a 340 km (210-mile) segment of the BAM between Ulak and Fevralsk in the far east this year, the defence ministry said.

Russian Railways, the state company that runs the vast national rail network, did not say how many troops it was using, but that they would be paid like any normal subcontractor.

"They (the military) have certain capacity and we have a need to involve them," said Andrei Makarov, deputy general director at Russian Railways.

He said using the army would cost between 2.5 billion and 3 billion roubles ($32.6 million-$39.17 million).

The number of foreign migrant workers in Russia fell from 9-11 million to 5.5 million last year as COVID-19 restrictions disrupted travel and many migrants left the country, TASS news agency said, quoting police data.

Makarov said Russian Railways was short of 3,000-4,000 foreign workers because of COVID-19 restrictions, and would continue using soldiers after the pandemic.

"It's mutually beneficial - we get the end product and an additional production force, while they get to conduct drills on a real, full-fledged construction site," he said.

Russian Railways also brought in troops in 2014, to help build a line bypassing Ukraine after a separatist conflict broke out in eastern Ukraine.

($1 = 76.5975 roubles)

(Reporting by Gleb Stolyarov; writing by Tom Balmforth; editing by Timothy Heritage) ((Tom.Balmforth@thomsonreuters.com))