The Carlton Bridge is a railroad vertical-lift bridge which carries one rail line over the Kennebec River between Bath and Woolwich, Maine. It was completed in 1927. Until August 1, 2000, it also carried two lanes of U.S. Route 1 (US 1) on its upper deck, after which the highway was transferred to the adjoining Sagadahoc Bridge and the road connection severed at the west end.[1] The east end is gated, and is accessible only by authorized vehicles.[2] The majority of the road deck remains but may be removed in the future. It is the last downstream fixed crossing of the Kennebec.
With the removal of US 1 from the bridge, its primary traffic is freight trains operated by the Central Maine and Quebec Railway that are bound for manufacturers in Thomaston, of which several pass over the bridge per week. It has also carried passenger excursion trains to Rockland, although the Maine Department of Transportation leased the line to another company that meant the end of passenger service after 2015.[3]