BNSF Railway Co., CN, Norfolk Southern Railway and Union Pacific Railroad are urging the Surface Transportation Board (STB) to apply more stringent standards in its review of Canadian Pacific's proposed acquisition of Kansas City Southern. In filings last week, the four Class Is asked the federal regulatory board to apply its 2001 merger guidelines when reviewing the proposed CP-KCS transaction, even though KCS, as the smallest Class Is, received a waiver from those guidelines. "The prior rules are antiquated, adopted over 40 years ago.