NEW YORK (MarketWatch) -- Railroad stocks took a beating Monday, dragging down the broader transport sector, after Kansas City Southern cut its sales outlook, citing the negative effects of lower oil prices and continued weakness in the Mexican peso.

Kansas City Southern’s stock KSU, -0.92% tumbled $8.94, or 7.7%, to the lowest level since July 1, 2014. Volume of 2.2 million shares at 12 p.m. Eastern was more than triple the full-day average, according to FactSet. Read more about Kansas City Southern’s lowered outlook.