If constructed, the new line would stretch from Miles City, Mont., south to Ashland, where Arch Coal is seeking to build one of several mines to access a 1.5 billion ton coal reserve, some of which is owned by the state. Estimated construction of the new railroad could take three years or more and cost upward of $490 million. BNSF spokeswoman Suann Lundsberg said it is up to federal officials when work could begin. Environmental groups and local landowners along the route have vowed to stop the project that is seen as integral in opening up the northern PRB coal reserves. Much of this coal would be destined for the Asian and Pacific Rim export markets and is one further puzzle piece necessary to Arch’s export plans.