Investigators from the national Transportation Safety Board were working with New York City engineers last week to find out why a test train derailed Sept. 27, damaging part of a newly built guideway on the $1.9-billion Airtrain project to John F. Kennedy Airport and killing the operator. As of Oct. 1, they were examining the possibility that not securing blocks of concrete used to approximate live loads within the test cars contributed to the collision with the guideway retaining wall.

Kelvin DeBourgh Jr., 23, of Jamaica, Queens, was an employee of Bombardier Transportation, Montreal, part of the consortium that built and was testing the system for the owner, the Port Authority of New York and New Jersey. The train, traveling at an unknown speed, rounded a curve of guideway on the airport fringe and crashed into the parapet, tearing open the front car and shearing away 150 ft of wall. DeBourgh was crushed.

NTSB spokesman Lauren Peduzzi says 16 concrete blocks, each 2,000 lb, had been placed laterally within the 60-ft-long cars--eight blocks in the first car and eight in the second. A third car was empty. The blocks apparently were not secured and shifted as the train rounded the curve. The role that played in the accident is still being determined, she says.

"The port authority and all the parties and contractors have pledged support" in aiding the investigation, says Pasquale DiFulco, a port authority spokesman. Testing of trains has been suspended and the accident will affect cost and schedule of Airtrain, which had been slated to open by year's end. The project had been on time and on budget. "It's too early for nitty-gritty details," he adds.

The consortium building the project under a design-build-operate-maintain agreement includes Slattery Skanska, Bombardier, and Perini Corp. New York City-based Parsons Brinckerhoff led the design effort. All firms deferred comment to the port authority and NTSB.

Peduzzi would not comment on whether using the concrete blocks to simulate passenger loads is a common practice. "That will be part of the investigation," she says. The first car is being examined on site while the others were taken to a railyard.

The 8.2-mile project includes the region's first use of precast segmental construction (ENR 8/21/2000 p. 74). Columns up to 6 ft in diameter and up to 44 ft tall support track up to 50 ft high. The accident occurred at an elevation of about half that height. The guideway, made of 20-ton, 32-ft-wide double box segments, loops in both directions for two miles around the terminals and splits to 3-mile legs leading to off-airport stations.

It was unclear how many segments topped with rail--a 14-year-old linear inducted motor technology licensed to Bombardier--would have to be replaced. The technology features free-rolling wheels magnetically propelled on a third rail made of aluminum composites, allowing the automatically driven cars to travel up to 60 mph once in service.