Task: Question Generation
Input (English): Passage: Transportation in Oklahoma is generated by an anchor system of Interstate Highways, inter-city rail lines, airports, inland ports, and mass transit networks. Situated along an integral point in the United States Interstate network, Oklahoma contains three primary Interstate highways and four auxiliary Interstate Highways. In Oklahoma City, Interstate 35 intersects with Interstate 44 and Interstate 40, forming one of the most important intersections along the United States highway system.More than 12,000 miles (19,000 km) of roads make up the state's major highway skeleton, including state-operated highways, ten turnpikes or major toll roads, and the longest drivable stretch of Route 66 in the nation. In 2008, Interstate 44 in Oklahoma City was Oklahoma's busiest highway, with a daily traffic volume of 123,300 cars. In 2010, the state had the nation's third-highest number of bridges classified as structurally deficient, with nearly 5,212 bridges in disrepair, including 235 National Highway System Bridges.Oklahoma's largest commercial airport is Will Rogers World Airport in Oklahoma City, averaging a yearly passenger count of more than 3.5 million (1.7 million boardings) in 2010. Tulsa International Airport, the state's second-largest commercial airport, served more than 1.3 million boardings in 2010. Between the two, six airlines operate in Oklahoma. In terms of traffic, R. L. Jones Jr. (Riverside) Airport in Tulsa is the state's busiest airport, with 335,826 takeoffs and landings in 2008. Oklahoma has over 150 public-use airports.Oklahoma is connected to the nation's rail network via Amtrak's Heartland Flyer, its only regional passenger rail line. It currently stretches from Oklahoma City to Fort Worth, Texas, though lawmakers began seeking funding in early 2007 to connect the Heartland Flyer to Tulsa.Two inland ports on rivers serve Oklahoma: the Port of Muskogee and the Tulsa Port of Catoosa. The state's only port handling international cargo, the Tulsa Port of Catoosa is the most inland ocean-going port in the nation and ships over two million tons of cargo each year. Both ports are on the McClellan–Kerr Arkansas River Navigation System, which connects barge traffic from Tulsa and Muskogee to the Mississippi River via the Verdigris and Arkansas rivers, contributing to one of the busiest waterways in the world.
Output (English): What is the name of Amtrack's rail line that currently stretches from Oklahoma City to Fort Worth Texas?