In 2009, Canadian Pacific moved 500 tank cars of petroleum products. In 2012, it moved 13,000 and could soon be moving as many as 70,000 tank cars. That's one reason the tank car backlog has reached about 48,000. "There has been a shortage of cars ever since crude on rail picked up," said Jean-Jacques Ruest, chief marketing officer at Canadian National. "There will be a shortage of cars in 2013; there will probably be a shortage of cars in 2014. After that we will see."