GLOVERSVILLE — After three years of delays, Trail Station Park in Gloversville has a new splash pad. The long-awaited Frontage Street project recently opened amid high temperatures and oppressive humidity gripping the Mohawk Valley. "It's been a real hit," said Mayor Vincent DeSantis. "A lot of people have been there almost all day, every day." Construction crews are about halfway finished planting trees around the spray-pad area and pouring foundation for the final stage of park construction: creating a new restroom and enclosed pavilion building. The mayor expects that phase, which is backed by $495,000 in state Downtown Revitalization Initiative…