Canadian Pacific Railway, the second-largest railroad in Canada, is exploring a takeover of U.S. carrier Norfolk Southern Corp. in a fresh attempt to consolidate the North American industry, according to people familiar with the matter.

Canadian Pacific is raising financing and has held early-stage merger talks with Norfolk Southern, which is valued at about $24 billion, said two of the people, who asked not to be identified because deliberations are private. Discussions are preliminary and talks may not progress or lead to a deal, they said. Representatives for Canadian Pacific and Norfolk declined to comment.

Norfolk Southern surged as much as 14%, the biggest intraday gain since 2001, while Canadian Pacific increased as much as 7.5% in Toronto. The Standard & Poor’s 500 Railroads Index, which tracks four U.S. carriers, rose as much as 5% to erase an earlier drop.

A move for Norfolk Southern, the second-biggest railroad in the eastern United States, would revive Canadian Pacific’s effort to build a transcontinental carrier after talks with CSX Corp. failed last year. In floating the idea of a CSX tie-up, Canadian Pacific CEO Hunter Harrison upended the long-held view in the industry that it was fruitless to even discuss another merger because regulators would object.

Read more here.