Ukraine wants Canada to lend its expertise and donate crucial railway parts to keep its embattled passenger and cargo rail system running as landmines and missile strikes threaten to stall the country's lifeline.

The rail system is vital to the war effort, and has been since the first days of the invasion that began one year ago this week.

Millions of people used trains to escape occupied cities and flee to neighbouring countries.

Thousands of wounded soldiers and civilians were also transported by rail to hospitals in safer parts of the country.

The railway is also how Ukraine moves aid and soldiers to front-line areas, where the fighting is most intense, and restores residents and supplies to territories returned to Ukrainian control after the Russian occupying forces leave.

'Constant attacks on rail and other critical infrastructure has rendered 20 per cent of the system unusable', said Oleksandr Pertsovskyi, the CEO of Ukrainian Railways' passenger company.

He added that more than 300 rail workers have also been killed.

"Very often they have to go right after the shelling ends, when it's still dangerous, to start repairs", he said in an interview from Kyiv, the capital city of Ukraine.