MTH RailKing....30-11046 and/or 30-11060. There was an earlier RailKing set, but it's no longer shown in the catalog, so I'll assume it's no longer available.
K-Line by Lionel made a really cool set...6-21445, Fire Figures. We (LHS) yet have one in stock, but they also show up from time to time at shows and internet auctions, too.
KD