The lead locomotive and all twelve cars derailed while approaching a bridge over Interstate 5 (I-5). The trailing locomotive remained on the rails. A number of automobiles on southbound I-5 were crushed and three people on board the train died. The train derailed a short distance from where the new route merges with the previous route.
Preliminary data from the data recorder showed that the train was traveling at 78 miles per hour (126 km/h), nearly 50 miles per hour (80 km/h) over the speed limit, when the incident happened.
Overview of new Amtrak Cascades inland route (red; to the south), showing accident location, and old shoreline route (green; to the north)
The Point Defiance Bypass was built from 2010 to 2017 as a replacement for the BNSF mainline that runs along the Puget Sound coast between the Nisqually River and Tacoma. The $181 million bypass, using an inland route that follows I-5, was built by the Washington State Department of Transportation (WSDOT) on right of way owned by Sound Transit, the regional transit authority. The Amtrak Cascades service is a joint effort of WSDOT and Oregon Department of Transportation, with Amtrak as a contracting operator. In the wake of the December 18 derailment, the safety of the bypass was questioned by elected officials. The 2006 Cascades corridor plan recommended that the curve and overpass where the derailment occurred be replaced with a straighter alignment, costing $412 million. The final plans omitted the overpass replacement, with a smaller budget of $180 million granted for the entire project.
Schematic site overview. The lead locomotive is the leftmost vehicle and stopped in the southbound lanes of Interstate 5. The train's rear locomotive is top-right. One car lies inverted under the bridge (shown in blue).
At 07:33 local time (15:33 UTC), the leading locomotive and twelve cars of the southbound Amtrak Cascades number 501 passenger train derailed southwest of DuPont. DuPont is about 40 mi (64 km) south of Seattle and about 5 mi (8.0 km) south of the Joint Base Lewis–McChord (JBLM) main gate. The train derailed while approaching the railroad bridge across southbound I-5 near Mounts Road, which contains a left-hand bend.
The lead locomotive, a new Siemens Charger No. 1402, and six rail cars went down the embankment to the west of the bridge (to the right, in the original direction of travel); the locomotive ended up on I-5 and spilled about 350 US gal (1,300 L) of fuel. Two further cars ended up on the bridge span, and three cars went off the railroad bridge abutment on the opposite side, some onto I-5. The trailing General Electric Genesis P42DC locomotive, No. 181, remained on the tracks. Seven vehicles, including two trucks, were damaged by the derailed cars of the train.
The three passengers killed in the derailment were train enthusiasts, including two members of rail advocacy group All Aboard Washington.
WSDOT-recommended detour routes on the evening of December 18 extended more than 70 mi (110 km) for the northern route with a travel time over 90 minutes, or alternatively, a southern route of 50 mi (80 km), with a travel time over 2 hours. Under normal conditions, driving 29 mi (47 km) from Tacoma to Olympia takes about 30 minutes.
Amtrak temporarily suspended service for south of Seattle for several hours because of the accident, resuming on the former coast route and the old Tacoma station. Southbound automobile traffic was rerouted away from I-5 by WSDOT until the site was cleared of debris and inspected. On December 18, JBLM allowed southbound traffic through from DuPont to State Route 510 near Lacey.
WSDOT announced on December 21 that it would not resume Amtrak service on the Point Defiance Bypass until positive train control is implemented in 2018. The accident caused at least $40 million in damage, including the cost of the trainset, damage to vehicles, and damage to the overpass.
Cleanup and freeway reopening
Some of the wrecked train cars were removed by trucks on December 19. Two southbound lanes of I-5 were reopened on December 20, with a reduced speed limit, as the cleanup and investigation continued. By the morning of December 21, all lanes of the freeway had been reopened.
The New York Times orial board said that the derailment is symptomatic of the Federal Government's failure to invest in infrastructure. It said that despite Trump seemingly acknowledging the problem, his administration's $630 million budget cuts to Amtrak, and a proposed plan to shift infrastructure costs down to state and local governments, would only serve to aggravate the problem.
NTSB engineers examine the locomotive event recorder two days after the derailment
The NTSB said the train was traveling at 80 mph (130 km/h) at a point soon before it derailed. The speed limit on the curved track segment where the derailment occurred is 30 mph (48 km/h), but the preceding track segment north of Mounts Road has a limit of 79 mph (127 km/h). An initial review by the NTSB said that the train data recorders had been recovered from both locomotives. The recorder showed that the engineer had commented on the train's excessive speed six seconds before the derailment, and applied the brakes. The lead locomotive was traveling at 78 mph (126 km/h) when recording stopped. The NTSB said their investigation will take 12 to 24 months. A preliminary report into the accident was published on January 4, 2018.
The NTSB interviewed the train's engineer, who suffered serious injuries, in January. He told investigators that he did not see the advance speed sign or milepost 18, mistakenly thinking he was at milepost 17. The engineer applied the train's brakes after seeing the final speed signpost, immediately north of the curve.
^"NTSB Conducts Initial Review of Amtrak Train Recorders" (Press release). National Transportation Safety Board. December 22, 2017. Retrieved December 23, 2017. About six seconds prior to the derailment, the engineer made a comment regarding an over speed condition. The engineer's actions were consistent with the application of the locomotive's brakes just before the recording ended. It did not appear the engineer placed the brake handle in emergency-braking mode. The recording ended as the locomotive was tilting and the crew was bracing for impact. The final recorded speed of the locomotive was 78 mph.
"Amtrak Cascades Train 501, operated by Amtrak, consisted of a Talgo constructed trainset containing 12 cars; (1) one power car, (1) one baggage car, (1) one lounge car, (1) one bistro car, (2) two business class cars, (6) six coach cars. There were (2) two locomotives, one on the front and one on the rear of the train. A standard Talgo coach car contains approximately 36 seats. The Talgo trainset and the Charger locomotive on the front of the train involved in the derailment are owned by WSDOT. Amtrak owns the locomotive on the rear of the train set."