The sun is just beginning to rise over the farm fields of the Herscher school district, 70 miles southwest of Chicago, but the youngest passengers on Bus 24 are already buzzing with excitement. The second, third and fourth graders climb aboard right on schedule — many decked out in holiday sweaters — and clamor for permission to sing Christmas carols. When bus driver Chris Hadley reminds them that they’re just days from their winter vacation, they respond with resounding cheers. But the children reserve some of their greatest enthusiasm for a less obvious crowd-pleaser: What, Hadley asks, do they think of their new electric school bus? “I love it!” “I looove it!” “Brilliant!” The Herscher district, with 25 full-sized electric school buses on the road, is a clean bus leader in Illinois and part of a growing trend fueled by $5 billion in federal funding. School districts across the country have committed to about 14,000 electric school buses, either by obtaining grant money, ordering buses or putting buses on the road, according to the Electric School Bus Initiative. And most of the increase has occurred in the last three years. “It’s just been a phenomenal climb,” said Electric School Bus Initiative Director Sue Gander. A Herscher school district student gets onto an electric school bus in Kankakee County on Dec.