India proposed Japanese pension funds invest in rail projects in the South Asian nation as the government prepares to spend more than $140 billion over five years upgrading its outdated tracks.

Indian Railways Minister Suresh Prabhu said he proposed the investment by Japan's pension funds during a series of meetings with Prime Minister Shinzo Abe and other ministers recently. The two sides also discussed doing joint research and development on railways, Prabhu said at a speech during a conference on India-Japan economic relations in New Delhi on Tuesday, without giving more specific details.

"Any pension funds will first desire security because capital is very important," Prabhu said. "Railways has a great advantage because they are very safe to invest, because railways are owned by the government of India, so therefore capital is not only guaranteed, but interest on that is also very grand."