When an Amtrak train near Interstate 5 in Washington state hurtled at what investigators stated was a speed of 80 miles an hour yesterday through a curve designed for only 30, the train careened off the track, killed three people and injured about 100.

Not in use on the newly refurbished train was a technology to stop a train automatically, a system mandated to be in place nationally next year but already in use by the Sonoma Marin-Area Rail Transit, which launched commuter service in September.

SMART trains are designed for a maximum speed of 79 mph in open sections such as north of Santa Rosa or between Petaluma and Novato, nearly the same speed as the Amtrak train that derailed. As trains go, these speeds are tame. Bullet trains in Japan reach 200 miles an hour. The world record for a maglev train was set in April 2015 at 374 miles an hour on an experimental track in Yamanashi.

Previous train crashes drove regulations to require the safety measure called positive-train-control technology. A June 2015 Amtrak derailment in Philadelphia where eight passengers died and some 200 were injured led the National Transportation Safety Board to investigate whether the train engineer was using his cell phone just before the crash. An ACE (Altamont Corridor Express) commuter train carrying more than 200 passengers between Fremont and Pleasanton crashed in March 2016 after a mudslide and tree landed on the Union Pacific track, sending a car into a creek and injuring 14 people.

“The federal government mandated that mainline railroads adopt a positive control technology” by 2018, said Bill Gamlen, SMART’s chief engineer, in a 2016 interview with North Bay Business Journal. SMART adopted the technology early. “If a train runs a red signal, it will bring that train to a stop. The technology will kick in and override the operator,” Gamlen said.

He oversees a team of six other engineers.

Positive train control governs excessive speed. The railroad sets up speed zones. “If an operator is going faster than that zone, he will get an initial warning, and he has a countdown timer in the cabin,” Gamlen said. “If he doesn’t bring his speed down within that zone, it will bring the train to a stop.”

The system also provides for worker safety, defined with speed zones in a particular area for track maintenance, for instance. In April 2016, an Amtrak train south of Philadelphia hit a backhoe, killing two employees and injuring about three dozen passengers.

Train engineers have no automatic-pilot option the way airline pilots do, according to Gamlen. “He’s operating the train. He’s got speed. He’s got the stop, doors and stations. For pre-recorded announcements, he pushes a button.”

SMART trains have two braking modes, one for normal deceleration for a “reasonable stop. Then there is full-out emergency braking,” he said. “If you can see the train, assume it can’t stop,” especially a heavy freight train. “It’s eye-opening. You have steel wheels on steel rails. The Kunze-Knorr brakes used on SMART trains are from Germany.

SMART, which cost nearly half a billion dollars, has 14 cars. Operated usually as two-car sets, the system will have seven sets. The doors and cars were designed in Japan. BART systems cost about $120 million per mile. Light rails costs about $50 million a mile. “We are running about $10 million a mile,” Gamlen said, excluding costs for acquiring right-of-way.

The Amtrak train that derailed Monday was on its first run. The tracks cost more than $180 million.

James Dunn covers technology, biotech, law, the food industry, and banking and finance. Reach him at: james.dunn@busjrnl.com or 707-521-4257