The Calais Branch is 127 miles (204 km) long and connects Brewer to Calais. It was constructed in 1898 and carried freight and passengers over the years. Passenger service was discontinued in 1957 and freight service was discontinued over the majority of the western end of the line in 1984. The line also includes a spur to Eastport which joins the Calais Branch at Ayers Junction.
The Calais Railway was chartered in 1832 as one of the first railway charters granted by the State of Maine. Construction started in 1835. The company was reorganized as the Calais Railroad in 1838 and opened a 2 miles (3.2 km) railway from Calais to Salmon Falls in 1839. Horses pulled cars over the railway until it was abandoned in 1841. The railway was re-activated and extended to Baring in 1852 as the Calais and Baring Railroad. Lewy's Island Railroad was chartered in 1854, and extended the railway from Baring through New Brunswick to Princeton in 1857. The railway was reorganized as the Saint Croix and Penobscot Railroad in 1870. The Washington County Railroad was chartered in 1893 to take control of the Saint Croix and Penobscot and connect it to the Maine Central Railroad Bar Harbor branch at Washington Junction. The Washington County Railroad was completed in 1898, and became the Calais branch in 1911 after Maine Central gained controlling stock interest in 1904.
The Calais branch was the longest of three Maine Central Eastern Division branches converging near Bangor. Trains leaving Bangor for Calais first traveled 31.5 miles (50.7 km) over the Bar Harbor branch. The Calais branch was considered to include the Bar Harbor branch after passenger service to Mount Desert Ferry was discontinued in 1937; and the first 1.2 miles (1.9 km) from Bangor to Brewer Junction have recently been considered part of the Bucksport branch.
- Milepost 0: Bangor
- Milepost 1.2: Brewer Junction with the 18-mile (29 km) Bucksport branch
- Milepost 10.5: Holden
- Milepost 17.3: Green Lake
- Milepost 29.1: Ellsworth
- Milepost 31.5: Washington Junction with the 10.8-mile (17.4 km) branch to Mount Desert Ferry
- Milepost 40.8: Franklin
- Milepost 55.8: Unionville
- Milepost 60.3: Cherryfield
- Milepost 66.1: Harrington
- Milepost 69.9: Columbia
- Milepost 77.2: Jonesboro
- Milepost 84.8: Whitneyville
- Milepost 88.7: Machias
- Milepost 110.6: Dennysville
- Milepost 117.4: Ayers Junction with the 16.4-mile (26.4 km) Eastport branch
- Milepost 130.0: Saint Croix Junction with the 17.8-mile (28.6 km) Princeton branch to Woodland
- Milepost 133.5: Calais
The last passenger train from Bangor to Calais ran on 25 November 1957. Diesel-era freight service often used ALCO RS-2s, RS-3s and RS-11s between Bangor and Calais as long as those Maine Central locomotives remained operational. A GE 44-ton switcher working out of Calais over the light rail of the Eastport branch was believed to be the last use of that model locomotive in regularly scheduled freight service on a class I railroad until the Eastport branch was abandoned in 1978. The paper mill at Woodland provided most of the traffic in the later years of operation. The mill originated or terminated over 6,000 carloads in 1973, while cumulative pulpwood and lumber loading at Ellsworth, Franklin, Cherryfield, Columbia Falls, Whitneyville, Machias, and Dennysville contributed less half that volume.
The section from Brewer to St. Croix Junction is currently abandoned and was acquired by the Maine Department of Transportation (MaineDOT) in 1987 for the purpose of preserving the rail corridor. The tracks are still intact, however they and the roadbed have been sporadically maintained by the state over the past two decades and significant deterioration has occurred.
In January 2006 the 30 mi (48 km) segment of the Calais Branch from Brewer to Washington Junction, east of Ellsworth was leased by owner MaineDOT to the not for profit Downeast Rail Heritage Preservation Trust. The Trust is currently working on rehabilitation of the line to begin excursion service from Ellsworth to Green Lake that will be called the Downeast Scenic Railroad.
The tracks from Washington Junction, To Ayers Junction have been removed for scrap, (as the rail was out of compliance with today's rail industry standards). The outdated tracks have been removed, with the intention of new 130 Lb rail and ties be laid in the future, as demand continues to grow. The State of Maine has stated that the Brewer to Calais section will be placed back in service as the Calais and surrounding areas continue to see economic growth. There are several corporations in the Downeast region expressing interest in restoring the once busy line as the need continues to rise.
An isolated extreme eastern section of the Calais Branch is still in operation from St. Croix Junction to Milltown where a connection is made with the New Brunswick Southern Railway at the Milltown Railway Bridge into Canada. At St. Croix Junction the Woodland Spur continues northwest to Woodland, crossing into New Brunswick (Canada) for several miles along the way. Together, these operable sections of the Calais Branch and the Woodland Spur measure 11.83 miles in length.
The Woodland Spur is the only Maine Central trackage that actually crossed into the Canadian province of New Brunswick. The spur was owned and operated by Pan Am Railways until being sold in 2012 to Woodland Rail; Woodland Rail has now contracted operation to New Brunswick Southern Railway.
- Peters, Bradley L. (1976). Maine Central Railroad Company. Maine Central Railroad.
- Maine Central Railroad (1917). Hand-Book of Officers, Agents, Stations and Sidings. Edwin B. Robertson.
- Johnson, Ron (1985). The Best of Maine Railroads. Portland Litho.
- The 470 Railroad Club (1981). Meet the Maine Central. KJ Printing.
- United States Department of Transportation (1974). Rail Service in the Midwest and Northeast Region. United States Government Printing Office.