Lionel 6-18108 Great Northern Non-Powered F-3 B Unit, 1993, New in Box August 15, 2026 By 0 : Up for review is the Lionel 6-18108 Great Northern Non-Powered F-3 B unit. The B unit and original Lionel box are in excellent condition. This colorful Great Northern B unit will be a great addition to your O gauge train layout.