Question: Pan Am Railways has a subsidiary in which former US Class I railroad in Maine?

full_context: Document 1: Montreal, Maine and Atlantic Railway: The Montreal, Maine and Atlantic Railway (reporting mark MMA) was a Class II freight railroad that operated in the U.S. states of Maine and Vermont and the Canadian province of Quebec between 2002 and 2014. It was headquartered in Hermon, Maine.
Document 2: Maine Central Railroad main line: The Maine Central Railroad Company main line extended from Portland, Maine, east to the Canada–US border with New Brunswick at the Saint Croix-Vanceboro Railway Bridge. It is the transportation artery linking Maine cities to the national railway network. Sections of the main line had been built by predecessor railroads consolidated as the Maine Central in 1862 and extended to the Canada–US border in 1882. Through the early 20th century, the main line was double track from South Portland to Royal Junction, where it split into a lower road through Brunswick and Augusta and a back road through Lewiston which converged at Waterville into single track to Bangor and points east. Westbound trains typically used the lower road with lighter grades, while eastbound trains of empty cars used the back road. This historical description does not include changes following purchase of the Maine Central Railroad by Guilford Transportation Industries in 1981 and subsequent operation as part of Pan Am Railways.
Document 3: Pan Am Railways: Pan Am Railways, Inc. (PAR), formerly known as Guilford Rail System (GRS) before March 2006, is an American holding company that owns and operates Class II regional railroads covering northern New England from Mattawamkeag, Maine, to Rotterdam Junction, New York. The primary subsidiaries of Pan Am Railways are Boston and Maine Corporation (reporting mark BM) , Maine Central Railroad Company (reporting mark MEC) , Portland Terminal Company (reporting mark PTM) , and Springfield Terminal Railway Company (reporting mark ST) ; BM and MEC are operated under lease by ST.
Document 4: List of SEPTA Rapid transit stations: The Southeastern Pennsylvania Transportation Authority contains two major rapid transit lines; The Market–Frankford Line and the Broad Street Line, both of which were inherited from the former Philadelphia Transportation Company, and originally built by the Philadelphia Rapid Transit Company. Both lines are officially part of the City Transit Division. It also includes the Norristown High Speed Line (Route 100) an interurban commuter rail line between Norristown, Pennsylvania and Upper Darby, Pennsylvania, originally owned by the Philadelphia and Western Railroad, then acquired by the Philadelphia Suburban Transportation Company, which itself was originally the Philadelphia and West Chester Traction Company.
Document 5: R.J. Corman Railroad Group: R.J. Corman Railroad Group, LLC is a privately owned railroad services and short line operating company headquartered in Nicholasville, KY, with field locations in 23 states. It was owned by Richard J. Corman, who established the company in 1973, and ran it until his death on August 23, 2013. The company owns eleven short-line railroads spanning Indiana, Kentucky, Mississippi, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, Texas, and West Virginia. The company serves all seven Class I railroads, many regional and short line railroads as well as various rail-served industries. These operations encompass an array of services, including: railroad construction, short line railroad operations, dispatch, industrial switching services, emergency response, track material logistics, distribution centers, signal design and construction, building eco-friendly locomotives, railroad worker training and an excursion dinner train.
Document 6: Rockland Branch: The Rockland Branch is a railroad from Brunswick, Maine to Rockland, Maine. A charter was granted in 1849 to build a railway from the Portland and Kennebec Railroad on the west side of the Kennebec River to Rockland. Construction through the rocky headlands of the Atlantic coast proved more expensive than anticipated. The Knox and Lincoln Railroad commenced service to Rockland in 1871 using a ferry to cross the Kennebec River between Bath and Woolwich. The Knox and Lincoln was leased by Maine Central Railroad in 1891, and became Maine Central's Rockland Branch in 1901. Maine Central purchased the Samoset destination hotel in nearby Glen Cove (a part of neighbouring Rockport) in 1912, and offered direct passenger service for summer visitors from the large eastern cities. Carlton bridge was completed in 1927 to carry the railroad and U.S. Route 1 over the Kennebec River. Maine Central sold the Samoset hotel in 1941, and the last Maine Central passenger train to Rockland was on 4 April 1959. The State of Maine purchased the branch in 1987 to prevent abandonment. The line has subsequently been operated by the Maine Coast Railroad, the Maine Eastern Railroad, and, beginning in 2016, the Central Maine and Quebec Railway.
Document 7: Conrail: Conrail, the Consolidated Rail Corporation, (reporting mark CR) , was the primary Class I railroad in the Northeastern United States between 1976 and 1999, when its routes were split between the CSX Corporation and Norfolk Southern Railway. Conrail, a portmanteau of "consolidated" and "rail" from the name of the company, operates now as a joint-subsidiary for some limited functions.
Document 8: CSX Transportation: CSX Transportation (reporting mark CSXT) is a Class I railroad in the United States. The main subsidiary of the CSX Corporation, the railroad is headquartered in Jacksonville, Florida, and owns about 21,000 route miles (34,000 km). CSX operates one of the three Class I railroads serving most of the East Coast, the other two being the Norfolk Southern Railway (NS) and Canadian Pacific Railway. It also serves the Canadian provinces of Ontario and Quebec. Together CSX and Norfolk Southern Railway have a duopoly over all east-west freight rail traffic east of the Mississippi River. As of August 8, 2017, CSX's total public stock value was slightly over $41.5 billion.
Document 9: NI Railways: NI Railways, also known as Northern Ireland Railways (NIR) and for a brief period Ulster Transport Railways (UTR), is the railway operator in Northern Ireland. NIR is a subsidiary of Translink, whose parent company is the Northern Ireland Transport Holding Company (NITHCo), and is one of two publicly owned train operators in the United Kingdom, the other being Direct Rail Services. It has a common Board of Management with the other two companies in the group, Ulsterbus and Metro (formerly Citybus). The rail network in Northern Ireland is not part of the National Rail network of Great Britain, nor does it use Standard Gauge; instead using Irish Gauge in common with the rest of the island of Ireland. Also, NIR is the only commercial non-heritage passenger operator in the United Kingdom to operate a vertical integration model, with responsibility of all aspects of the network including running trains, maintaining rolling stock and infrastructure, and pricing.
Document 10: Amtrak: The National Railroad Passenger Corporation, doing business as Amtrak , is a passenger railroad service that provides medium- and long-distance intercity service in the contiguous United States. Founded in 1971 to take over most of the remaining U.S. passenger rail services, it is partially government funded yet operated and managed as a for-profit corporation.
Document 11: Maine Central Railroad Company: The Maine Central Railroad Company (reporting mark MEC) was a former U. S. Class I railroad in central and southern Maine. It was chartered in 1856 and began operations in 1862. By 1884, Maine Central was the longest railroad in New England. Maine Central had expanded to 1,358 mi when the United States Railroad Administration assumed control in 1917. The main line extended from South Portland, Maine, east to the Canada–United States border with New Brunswick, and a Mountain Division extended west from Portland to Vermont and north into Quebec. The main line was double track from South Portland to Royal Junction, where it split into a "lower road" through Brunswick and Augusta and a "back road" through Lewiston which converged at Waterville into single track to Bangor and points east. Branch lines served the industrial center of Rumford, a resort hotel on Moosehead Lake, and coastal communities from Bath to Eastport.
Document 12: Pennsylvania Railroad: The Pennsylvania Railroad (reporting mark PRR) (or Pennsylvania Railroad Company and also known the "Pennsy") was an American Class I railroad that was established in 1846 and was headquartered in Philadelphia, Pennsylvania. It was called the Pennsylvania Railroad because it was established in the state of Pennsylvania.
Document 13: Rockland Railroad Station: The Rockland Railroad Station is a railway station located at Union and Pleasant Streets in Rockland, Maine. It is the eastern terminus of the Rockland Branch, a state-owned track connecting Rockland and Brunswick. The historic station building was built in 1917 by the Maine Central Railroad, and is listed on the National Register of Historic Places; it presently houses a restaurant, and served for a time as Rockland's city hall. The line is presently inactive, having most recently had seasonal passenger service from 2004 to 2015 operated by the Maine Eastern Railroad. The line has been leased to the Central Maine and Quebec Railway, which is planning to reintroduce service on the line.
Document 14: Central Maine and Quebec Railway: The Central Maine & Québec Railway (reporting mark CMQ) is a Class III freight railroad operating in the U.S. states of Maine and Vermont and the Canadian province of Quebec with headquarters in New York, NY. It is owned by Railroad Acquisition Holdings, LLC, a subsidiary of Fortress Investment Group, LLC.
Document 15: St. Johnsbury and Lamoille County Railroad: The St. Johnsbury and Lamoille County Railroad (StJ&LC) was constructed in the 1870s as the Vermont Division of the Portland and Ogdensburg Railway to connect the Great Lakes with the seaport of Portland, Maine. The westerly connection with the Great Lakes was never made. The eastern end of the Vermont Division was leased to the Maine Central Railroad in 1912, and the remainder of the line became a subsidiary of the Boston and Maine Railroad. The Boston & Maine operated their segment as the St. Johnsbury and Lake Champlain Railroad after 1925. This segment was reorganized as the St. Johnsbury and Lamoille County Railroad in 1948.
ground_truth: Maine Central Railroad Company