RAILROAD ACCIDENT REPORT: HAZARDOUS MATERIALS ACCIDENT AT THE SOUTHERN PACIFIC TRANSPORTATION COMPANY'S ENGLEWOOD YARD IN HOUSTON, TEXAS SEPTEMBER 21, 1974
About noon on September 21, 1974, 2 loaded "jumbo" tank cars, cars 17 and 18 of a 145-car complement, were uncoupled as a unit at the crest of the gravity hump in the Southern Pacific Transportation Company's (SP) Englewood Yard at Houston, Texas. The two cars passed through the hump master retarder and group retarder without being slowed and accelerated as they moved down the grade into bowl track 1. At a speed of 18 to 20 mph, the two tank cars impacted an empty tank car. Upon imppact, the coupler of the empty tank car rode over the coupler of car 17 and punctured the tank head. Butadiene spilled from the car and formed a vapor cloud, which dispersed over the area. AFter 2 to 3 minutes, the vapor exploded violently; as a result, 1 person died and 235 were injured. Total damages amounted to about $13 million, which included the destruction of 231 railroad cars and substantial damage to 282 others. The National Transportation Safety Board determines that the probable cause of the overspeed impact was the failure of the retarding system to slow the two coupled tank cars and the absence of a backup system to control cars which pass through the retarders at excessive speeds. The failure of the retarding system was caused by foreign substances on the wheels of the two cars that preceded the two tank cars through the retarders. Contributing to the accident was the failure of the Southern Pacific Transportation Company to enforce procedures to exclude cars with a foreign substance on their wheels from the humping system, and the Shell Oil Company's failure, after notification of the hazard, to eliminate spilled epoxy resin from the flangeways of their track.
- This report contains Railroad Safety Recommendations R-75-28 through R-75-30.
National Transportation Safety BoardOffice of Surface Transportation Safety
Washington, DC USA 20594
- Publication Date: 1975-5-21
- Pagination: 39 p.
- TRT Terms: Butadiene; Classification yards; Crash investigation; Crashes; Explosions; Freight cars; Hazardous materials; Hump yards; Inspection; Safety
- Identifier Terms: Southern Pacific Railroad
- Old TRIS Terms: Freight car inspection; Humping; Tank car heads
- Subject Areas: Railroads; Safety and Human Factors; Terminals and Facilities;
- Accession Number: 00099182
- Record Type: Publication
- Source Agency: National Transportation Safety Board
- Report/Paper Numbers: NTSB-RAR-75-7
- Files: NTIS, TRIS
- Created Date: Aug 27 1976 12:00AM