Laura Lee Hope 
Bobbsey Twins at the County Fair [PDF ebook] 

The Bobbsey twins are having fun at a church picnic when a mysterious shipment arrives in town. It’s a beautiful merry-go-round that needs to be repaired before it can be put into use at the upcoming county fair. Because Nan, Bert, Flossie and Freddie are so clearly fascinated by the merry-go-round, Mr. Bobbsey decides to take the family on a trip to visit the fair.