Providence Plantation, a center for living history presentations about 18th century frontier life at 300 Textor Hill Road, Evans City, will host a Christmas evening program featuring a character interpretation of Christopher Gist's two Christmas experiences on the Ohio River frontier, 18th century music, and a Christmas meal based on period recipes from 4 to 7 p.m. Saturday. Cost is $30, and reservations are necessary. Call 724-538-8818 or visit www.providenceplantationpa.org.

Harmony Museum, Mercer Street, Harmony has expanded its Christmas model railroad display. The antique Yobp-Eckstein log village and O gauge railroad is joined by an HO gauge layout. Also new is a “hands-on” wood push train for preschoolers on a tiny child-level table. Guided museum tours are available from 1 to 4 p.m. daily except Mondays. Reservations are suggested for weekends and required for groups. Call 724-452-7341 or 888-821-4822, or visit the www.harmonymuseum.org.

Carnegie Science Center, North Side, hosts Locomotion Weekend featuring dozens of model train layouts, rail-related exhibits, and hands-on activities for train enthusiasts from 10 a.m. to 7 p.m. Saturday and 10 a.m. to 5 p.m. Sunday. Breakfast Express, sponsored by Eat 'n Park, involves a journey inspired by the classic holiday film, “The Polar Express: An IMAX® Experience” on Dec. 15 and 22. Newly opened is Spaceplace featuring a two-story walk-in replica of the International Space Station. Call 412-237-3400 or visit CarnegieScienceCenter.org.