The county’s mobile preschool classroom just got a major upgrade. The Marin County Free Library’s FLAGship Bus was retired this month after 18 years and 147,000 miles in favor of a more sustainable vehicle: the Learning Bus. The 30-foot bus, stocked with books, games, arts and crafts for children under 5, uses a hybrid system that reduces emissions and fuel consumption. The Wi-Fi, air conditioning, lighting and computer system can be powered without a running engine for eight hours on a single charge, aided by regenerative braking and solar panels. The sustainable bus is a far cry from the FLAGship, which averaged five miles per gallon and was in the maintenance shop often over the past few years. “We kept repairing it because the vehicle is so vital to the library’s equity initiative and served residents who were isolated because of geography, finances or the lack of English language skills,” said Bonny White, deputy director of the Marin County Free Library. The bus cost $344,000, funded by community donations, county funds, Measure A tax proceeds and the Marin County Library Foundation. The bus will resume its regular schedule next week, visiting the San Geronimo Valley Community Center and Tomales Elementary on Tuesdays, then Toby’s Playground and the Bolinas Library on Wednesdays. For the schedule, visit marinlibrary.org/learningbus.