page_title: Vought Airtrans
section_title: Guideways and power supply
hierarchical_section_title: Vought Airtrans / System operations / Guideways and power supply
caption_attribution_description: Airtrans Power
context_page_description: LTV's Airtrans was an automated people mover system that operated at Dallas-Fort Worth International Airport between 1974 and 2005. The adaptable people mover was utilized for several separate systems: the Airport Train, Employee Train, American Airlines TrAAin and utility service. All systems utilized the same guideways and vehicle base but served different stations to create various routes.
  After 30 years of service the system's 1970s technology was no longer adequate for the expanding airport's needs, and in 2005 it was replaced by the current Skylink system. While most of the system was auctioned and sold for scrap, some guideways and stations remain. Airtrans moved nearly 5 million people in its first year of operation; by the end of its life it had served over 250 million passengers.
  Airtrans technology was expected to be deployed in similar mass transit systems around the US. In Japan, the system was licensed by a consortium formed between Niigata Engineering and Sumitomo Corporation for similar deployments there.
context_section_description: Guideways were made of concrete and based on highway construction techniques. The varying topography of the airport resulted in both aerial and ground level guideways winding their way over and under public roadways. As the guideway entered the semicircular terminals or remote parking areas, it remained at ground/ramp level and under the terminal building. At these terminal areas the guideway branched out to serve various stations, bypass tracks and vehicle storage sidings. Additional bypass guideways were constructed as the airport expanded. At several locations along the guideway tug sidings were located near the airport service road, allowing a disabled vehicle to be removed from the guideway and towed to the maintenance facility.
  The guideway was uni-directional, with all vehicles traveling around the airport in a counter-clockwise direction. The top of the guideway walls contained rails that steered the vehicles. Small urethane wheels on either side of the vehicle engaged the rail and were mechanically linked to a conventional steering suspension on the main wheels. Switching was provided by switching bars on either side of the guideway that raised or lowered to trap one of the two sets of guidance wheels under them. The switch was adapted from existing fail-safe switches used on railways.
  Power was supplied in three-phase form at 480 VAC through three conductor strips on the guideway wall. Below the conductors was a common ground, and above it was an inductive loop used for signalling. Mechanical "feelers" extending from the corners of the vehicle with brushes on their ends engaged the conductors. Power was rectified and fed into a DC motor, which was attached to a conventional differential and then to the wheels at one end. The motor was bi-directional and was switched depending on the vehicle's direction of travel.
caption: A wheel of an Airtran vehicle
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