While the Great Scale Model Train show is dominated by HO (just like the hobby), it is a big show, and there has always been plenty of 3R O gauge. Some of my best finds have been at that show. My other favorite shows are Allentown (Spring and Fall), Strasburg 2R scale shows, and, of course, TCA York, all within 2 1/2 hours of Baltimore.
It's a shame that MB Kleins in Timonium MD closed their retail store. They still do business as ModelTrainStuff.com. Another store close to Baltimore is Star Hobbies on Rt 50 right before the Bay Bridge. They have a decent selection of O gauge.
Bob
