Question: Nebraska Central airlines is based out of the same state as what largest in United States rail system?

Context paragraphs:
Pittsburgh Light Rail: The Pittsburgh Light Rail (commonly known as The T) is a 26.2 mi light rail system in Pittsburgh, Pennsylvania; it functions as a subway in Downtown Pittsburgh and largely as an at-grade light rail service in the suburbs south of the city.  The system is largely linear in a north-south direction, with one terminus just north of Pittsburgh's central business district and two termini in the South Hills.  The system is owned and operated by the Port Authority of Allegheny County.  It is the successor system to the streetcar network formerly operated by Pittsburgh Railways, the oldest portions of which date to 1903.  The Pittsburgh light rail lines are vestigial from the city's streetcar days, and is one of only three light rail systems in the United States that continues to use the Pennsylvania Trolley (broad) gauge rail on its lines instead of .  Pittsburgh is one of the few North American cities that have continued to operate light rail systems in an uninterrupted evolution from the first-generation streetcar era, along with Boston, Cleveland, New Orleans, Newark, Philadelphia, San Francisco and Toronto.

Nebraska Central Railroad: The Nebraska Central Railroad (reporting mark NCRC) is a shortline railroad that operates about 340 mi of track solely in Nebraska.  It runs on former Union Pacific Railroad and BNSF Railway track in central Nebraska.  It is a subsidiary of the Rio Grande Pacific Corporation.

Metra: Metra (reporting mark METX) is a commuter railroad in the Chicago metropolitan area.  The railroad operates 241 stations on 11 different rail lines.  It is the fourth busiest commuter rail system in the United States by ridership and the largest and busiest commuter rail system outside the New York City metropolitan area.  There were 83.4 million passenger rides in 2014, up 1.3% from the previous year.  The estimated busiest day for Metra ridership occurred on Nov. 4, 2016—the day of the Chicago Cubs 2016 World Series victory rally.

San Diego Trolley: The San Diego Trolley (reporting mark SDTI) is a light rail system operating in the metropolitan area of San Diego.  It is known colloquially as The Trolley.  The Trolley's operator, San Diego Trolley, Inc. (SDTI), is a subsidiary of the San Diego Metropolitan Transit System (MTS).  The Trolley began service on July 26, 1981, making it the oldest of the "second generation" light rail systems in the United States.  The entire Trolley network serves 53 stations, and comprises 53.5 mi of route, and three primary lines named the Blue Line, the Orange Line, and the Green Line, as well as a supplementary heritage streetcar downtown circulator known as the Silver Line that operates on select weekdays, weekends and holidays.  In Q4 2014, the Trolley was the 4th most-ridden light rail system in the United States, with an average of 119,800 riders per weekday.

List of Metra stations: Metra is the commuter rail system serving the Chicago metropolitan area in Illinois and Wisconsin, servicing Cook, DuPage, Kane, Lake, McHenry, and Will Counties in northeastern Illinois and the city of Kenosha in southern Wisconsin.  It is one of three of the Regional Transportation Authority's service boards.  With an average weekday ridership of 294,600 in 2015, Metra is the fourth busiest commuter rail system in the United States, only behind New York City metropolitan area systems.  The Metra system has a total of 241 active stations spread out on 11 rail lines with 487.5 mi of tracks.  s of August 2017 , there are no actively planned extensions of the Metra system, although a new station is under construction in Romeoville, Illinois.  Construction is expected to be completed in Fall 2017.

DART Light Rail: DART Light Rail is a light rail system in Dallas, Texas and its suburbs owned and operated by Dallas Area Rapid Transit.  The system comprises 93 mi among its four lines — the Red Line , the Blue Line , the Green Line , and the Orange Line .  It is the longest light rail system in the United States.  As of the fourth quarter of 2014, the system has an average weekday ridership of 101,800, making it the largest light rail system in the Southern United States by ridership, and the seventh largest in the United States by ridership.  As of Fiscal Year 2015, the system average weekday riderships had fallen to 97,800.  (The system utilizes 163 light rail trains manufactured by Kinki Sharyo, with all trains being converted to "Super" LRVs which feature level boarding and higher passenger capacity.

Union Pacific Railroad: The Union Pacific Railroad (or Union Pacific Railroad Company and simply Union Pacific) is a freight hauling railroad that operates 8,500 locomotives over 32,100 route-miles in 23 states west of Chicago and New Orleans.  The Union Pacific Railroad system is the largest in the United States and it is one of the world's largest transportation companies.  The Union Pacific Railroad is the principal operating company of the Union Pacific Corporation (); both are headquartered in Omaha, Nebraska.

METRORail: METRORail is the 23.8 mi light rail system in Houston, Texas (USA).  As of 2015, the METRORail has an average weekday ridership of 60,600 and total annual ridership of 16,500,400.  After Dallas' DART Light Rail, METRORail ranks as the second most-traveled light rail system in the Southern United States and the 12th most-traveled light rail system in the United States.  METRORail is operated by the Metropolitan Transit Authority of Harris County (METRO).

North Central Airlines: North Central Airlines was a regional airline in the midwestern United States.  Founded as Wisconsin Central Airlines in 1944 in Clintonville, Wisconsin, the company moved to Madison in 1947.  This is also when the "Herman the duck" logo was born on Wisconsin Central's first Lockheed Electra 10A, NC14262, in 1948.  North Central's headquarters were moved to Minneapolis–St. Paul in 1952.

List of Los Angeles Metro Rail stations: In Los Angeles County, California, the Metro Rail system, is a combined rapid transit and light rail system, operated by the Los Angeles County Metropolitan Transportation Authority (LACMTA).  The system is composed of two rapid transit lines and four light rail lines that run on 105.8 mi of track.  As of March 2012, Los Angeles County Metro Rail serves an average of 323,870 passengers each weekday, 192,943 each Saturday, and 146,646 each Sunday.  Metro Rail is one of the largest rapid transit and light rail systems in the United States by ridership.  This is complemented by Metro's two Metro Liner bus rapid transit lines.

Supporting paragraphs: Nebraska Central Railroad Union Pacific Railroad
Answer: Union Pacific Railroad