Page:NTSB RAR-73-5.pdf/21

- 16 - * A service brake application was made as train 720 passed Signal 3-3.60 at a speed of 60 m.p.h. The speed was reduced to 30 m.p.h., and that speed was maintained until the train was 500 feet south of the collision point, where an emergency application of the brakes was made. The train stopped 299 feet south of the collision point.


 * The emergency braking distance of train 720 from various initial speeds was measured. Results are shown below:


 * The red marker lights on the rear of 416 were not visible during any of the tests until after the end of the car became discernible.

Signal system. Postaccident tests were performed on the signal system by ICG employees and by representatives of the Federal Railroad Administration (FRA). No defects or abnormalities were found which could have contributed to the accident.

Train equipment. The collision posts of the Highliner car struck by 720 failed in the weld which attached the shear attachment plate to the underframe. Tests disclosed incomplete fusion between the plate and about 75 percent of the weld. The bottom edge of the plate was bevelled to permit the weld to penetrate through the plate to the underframe from one side. However, the bevel of the shear attachment plate extended only five-sixteenths of an inch into the plate, instead of the full one-half inch as designed. An additional 1/2-inch fillet weld which had been applied adjacent to the original weld failed in the parent materials of the underframe and shear plate. The plug welds which attached the reinforcing plate to the collision posts were fused incompletely. Further description of the design and failures of the collision posts can be found in Appendix G, which contains an interim recommendation made by the Safety Board to the FRA on April 25, 1973.