Freezing rain has a sound — a small ticking on the windows along Kaighn Avenue — and it usually starts near midnight. Root 24 HR's Plumbing Inc answers the winter side of Camden at whatever hour the weather picks, plowing, shoveling, salting and sanding driveways, walks and lots until the ice loses its grip. The city gives you long straight runs off Broadway and then a tight alley that has to be done by hand; both get done the same night. There's a real satisfaction in returning at dawn to a lot you cleared at two and finding it still open, still dark asphalt under the streetlights. Whatever the sky decides between Broadway and the river, somebody is awake for it.