KINGSPORT — The “castle” replacement project at Johnson Elementary is finally a go, meaning the playground that turns 28 years old next month is about to be replaced for the benefit of generations of children to come. Because fundraising efforts have reached the 90 percent threshold, the iconic 1990 playground — which got its name from its distinctive design and has been used by countless children — will be replaced in a community build March 5-10. Johnson Principal Stacy Edwards said that details are still being worked out and that the project website, www.castleofkingsport.com, soon will be updated.