Canadian National Railway Co. made a roughly $30 billion bid for Kansas City Southern, kicking off a bidding war for a railroad operator that has already agreed to a sale to another Canadian rival.

Canadian National offered $325 for each Kansas City Southern share, including $200 in cash and 1.059 Canadian National shares. The company stated that the offer represents a 21% premium to Canadian Pacific Railway Ltd.’s agreement to pay $ 275 a share, including $90 in cash. A roughly $25 billion deal was reached last month.

The move sets up a skirmish for a key strategic asset composed to benefit from an expected surge in economic activity as the world resurfaces from the coronavirus pandemic. Either combination would create the first freight-rail network connecting the US, Mexico and Canada by linking ports in three different countries.

Kansas City Southern, the smallest of the five main freight railroads in the US, plays a large role in the US-Mexico trade, with a network extending across both countries. Its trains bring autos and other industrial products up from factories south of the border into Texas and the Midwest and haul US farm goods back to Mexico. It also runs a rail link along the Panama Canal.