The Brief FDOT is studying a possible SunRail extension from Osceola into Polk County. SunRail may soon expand its commuter rail service from Osceola County into Polk County, officials said Monday. What we know:SunRail could soon stretch beyond its current route, with a proposed extension from Osceola County into Polk County. Transportation officials and local leaders have long considered rail expansion as a way to ease congestion and provide alternatives to driving in the rapidly developing region. Big picture view:If approved, the extension could connect fast-growing Polk County communities with the broader commuter rail system, easing pressure on road infrastructure and supporting economic development.