Brandon Hollinger, age 9, of Franklin County, right relaxes in the huge wheel of John Deere chopper during the Keystone Farm show at the York Expo. Trout attended the 19th annual Keystone Farm Show on Wednesday along with his son and his grandson. Trout, a Perry County resident, said he is “fairly progressive” and was interested in asking questions about “anything new and innovative. The Keystone Farm Show is for farmers like Trout, show manager Ken Maring said. The show, the largest commercial farm equipment and service provider trade show in Pennsylvania, has grown and transformed year to year. The proof is in the number of vendors and size of attendance, Maring said. This year, he said, he had to utilize all of the York Fairgrounds' buildings and an outdoor tent. Next year, for the 20th annual Keystone Farm Show, he said he hopes to add another tent. The show began with 88 vendors and has grown to 480 vendors. At the winter show, Maring said farmers are "doing their buying, and.