One-by-one, they walked in step behind one another around the shedrow. Three horses, the first led by trainer Desmond Fogarty on lead line, with a third bringing up the rear with Darren Nagle at his side. The slow, methodical pace of the exercise walk for the horses on a miserable Wednesday morning on the grounds of the Springdale Race Course was in stark opposition to the meteoric rise of Nagle, a 23-year-old native of County Cork, Ireland, who continues his ascent toward the top of the National Steeplechase Association leader board.