Whittier is one of only two Alaskan seaports that are ice-free all year. The other, Seward, would have been very difficult to run major freight traffic over, as there is a 3% grade on parts of the line (requiring six or more locomotives for a train that can be pulled from Whittier with two). Whittier is also a point on the Alaska Marine Highway System. This strategic importance convinced the government to build the original rail-only Whittier Tunnel. After the upgrade, it's now called the Anton Anderson Memorial Tunnel.