NTSB Press Release

National Transportation Safety Board
Office of Public Affairs


August 27, 2004

The National Transportation Safety Board today released the following information on its investigation of the June 28, 2004 collision of Union Pacific (UP) and Burlington Northern Santa Fe (BNSF) trains and subsequent chlorine release at Macdona, Texas near San Antonio.

Rail Car Examination

Two rail cars, the chlorine tank car, ACFX 86305, the 16th car in the train and a rail flat car XTTX137323, the 12th car in the train, were taken to a tank car facility in Texarkana, Arkansas. At the facility the investigation team led by the NTSB Hazardous Materials Group Chairman and an NTSB metallurgist conducted detailed examinations of both cars including an examination of the relative orientation of the major indentations in both cars.

The chlorine tank car had an approximate 2-inch by 11- inch puncture at one end of the tank and the trailing end of the flat car was buckled inwards. Three sections of the tank car were cut out and sent to the NTSB laboratory in Washington, D.C., including the punctured section of the tank head, a non-punctured section of the tank head, and a section of the tank car side shell. The NTSB materials laboratory will determine the failure mode and the metallurgical properties of the material used to fabricate the tank car head and side shell.

Toxicology Tests

In accordance with Federal Railroad Administration regulations, post accident toxicological testing was conducted on specimens from the crews of both trains.

Test results were negative for the UP engineer and the BNSF engineer and conductor. Testing for the UP conductor detected a blood alcohol concentration of 0.013%.

Train Crewmembers

The BNSF crew had gone on duty at San Antonio at 6:15 p.m. on the evening before the collision, and had been on duty about 10 hours and 33 minutes at the time of the collision.

The UP crew had gone on duty at San Antonio at 2:45 a.m. They had been on duty about 2 hours and 18 minutes at the time of the collision. The UP engineer was off duty for 14 hours and 15 minutes before reporting for work on the day of the accident. The conductor of the UP train had been off duty for almost 28 hours before reporting for duty.

NTSB Office of Public Affairs: (202) 314-6100



The National Transportation Safety Board (NTSB) is an independent federal agency charged with determining the probable cause
of transportation accidents, promoting transportation safety, and assisting victims of transportation accidents and their families.