January on Gun Hill Road: the el rumbling overhead, awnings loaded, and every driveway in Williamsbridge waiting on somebody with a plow. SYLVESTERS HOME IMPROVEMENT LLC answers that — plowing, shoveling walkways and steps, cutting out the snow the city plows bank in, salting and sanding so the ice does not return by nightfall. That banked-in driveway is the real Bronx winter problem, and breaking through the ridge is honest, useful work. There is a plain pleasure in watching a car pull out clean onto White Plains Road at seven in the morning. Storm after storm, that is the job.