In an annual spectacle to promote this weekend’s Halifax County and Antique Machinery Festival, antique tractors and other vehicles paraded around South Boston on Saturday. The tractors lined up at Berry Hill Presbyterian Church at 8:30 a.m. before venturing to Berry Hill Plantation. The parade then marked to Windmill Farm Bake Shop in the Hupp’s Mill Shopping Center.  Now in its 18th year, the Halifax County and Antique Machinery Festival offers two days of exhibits of antique tractors, machinery and more from 9 a.m. to 6 p.m.  Friday and Saturday at Halifax County Fairgrounds.