No positive train control on train that derailed over Interstate 5

December 18, 2017  - By
Photo: NTSB

Photo: National Transportation Safety Board

Multiple injuries and fatalities have been reported after an Amtrak train derailed Dec. 18 on the inaugural run of a new high-speed service linking Seattle and Portland.

Train 501 was going south when it derailed while crossing a bridge over Interstate 5 (I-5) near DuPont, Washington, around 7:40 a.m. Pacific Time, causing at least one car to fall onto the freeway below. At least six are dead, none of them motorists on the freeway.

Amtrak Cascades Train 501 was making a southbound run from Seattle to Portland. The Interstate northbound route is closed.

The Amtrak/Cascade trains are pulled by new Charger locomotive. While equipped with positive train control systems that automatically stop trains when trouble is detected, the PTC system isn’t due to be activated until 2018.

The last serious train accident in the United States took place May 12, 2015, when the Amtrak 188 connecting Washington to New York with 243 people on board derailed at the entrance of a curve while the train was launched at 100 miles per hour, more than twice the speed allowed. The accident killed eight people and injured more than 200.

PTC makes it possible to monitor the location of the train and the speed at which it travels, by using GPS and sensors placed both in the trains and along the tracks.

A computer system centralises the data and prevents any excess speed, any red light or collision with another convoy by acting on the locomotive instead of the driver, to curb if it goes too fast, or stop it completely if an obstacle has been detected on the tracks for example.

The accident comes just a week after the mayor of Lakewood, a nearby town, warned that high speeds on this segment of track could causes accidents.

According to John F. Banzhaf, the accident could have been avoided with an inexpensive GPS-based speed control system. Banzhaf is an MIT-trained professor who is also an inventor with two U.S. patents.

Banzhaf argues that trains should be using a simple GPS-based system to prevent excessive speeds, and not waiting for the delayed and expensive PTC.

“Rather than waiting for so-called positive train control [PTC] systems which may not be operational soon, there is a much simpler and much less expensive GPS-only speed control system for trains which could be put into operation much more quickly, and at only a fraction of the cost of PTC,” Banzhaf said.

“It is also so simple that its basic principle is already in use in millions of automobiles and trucks now on the roads.

The new routing of the trains, which began Monday, uses Sound Transit tracks that go through Lakewood and along I-5 in the area. In all, the new routing was meant to shave about 10 minutes on the travel time and make for more on-time trips, as the Amtrak trains would no longer have to share single-track tunnels with BNSF trains near Point Defiance and along southern Puget Sound.

“One reason that PTC is so expensive, time-consuming to establish, and difficult to install is that it is designed to do far more than the simplest but most vital task of keeping trains from exceeding the speed limit — e.g., also dealing with switches left in the wrong position, hijackings, natural disasters, etc.

“It is therefore a very complex system which requires not just GPS units in each locomotive, but also many thousands of signaling devices along sections of about 140,000 miles of track which transmit cab codes to antennas on railroad cars.

“Unfortunately, for PTC to work properly, there must be close cooperation and coordination between the many different entities which own the different tracks to which the devices are attached, and the owners of over 500 different railroad companies which may run on these many different tracks.

“All of the devices must also be able to communicate seamlessly with each other, and much of the delay in installing the system has been caused by the need to unify dozens of different systems, obtain permission to use the radio frequencies necessary for the devices to flawlessly exchange information, and related coordination problems…

“Since automobile GPS units can show not only the car’s speed, but also the speed limit on that section of the road, they could also be mounted on each locomotive and prevent the posted speed from being exceeded — completely independent of the tracks on which they are traveling, and without the need for any other sensing devices, cooperation with other companies, communication between devices, etc.”

Read Banzhaf’s full blog at

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About the Author: Tracy Cozzens

Senior Editor Tracy Cozzens joined GPS World magazine in 2006. She also is editor of GPS World’s newsletters and the sister website Geospatial Solutions. She has worked in government, for non-profits, and in corporate communications, editing a variety of publications for audiences ranging from federal government contractors to teachers.