Pine Mountain Route Flint River. Photo by Doug Bradley. Some rights reserved. The Pine Mountain Route was a marketing name of the Macon & Birmingham Railroad. Between Woodbury and Thomaston the railroad crossed the Flint River at the beginning of the stream's scenic passage through Pine Mountain. The M&B was also known as the LaGrange Route. RailGa.com. Georgia's Railroad History & Heritage. © Steve Storey Railroad History | The Depot List | Locomotives On Display | Odds & Ends | Sources & References | Home