The Big Hill! The name originally given the "Big Hill" was the original 4.5% eastbound grade out of Field, BC, that directly assaulted the Continental Divide, while a better solution could be engineered. Canada Highway 1 mostly follows this original line. The grade was realigned in 1909 with the Spriral Tunnels. This lowered most of the grade to 2.2%. However this section from Field to the Cathedral Tunnel is still 2.4% making it one of the steepest sections of mainline grade in North America. Railroaders still often refer to this mountain as "The Big Hill"....