The third person killed in the deadly Amtrak crash has been identified as a convicted sex offender found in possession of child porn while working in IT at a college.

Benjamin Gran, 40, of Auburn, Washington, died of multiple traumatic injuries on Monday when the Amtrak Cascades train 501 plummeted off the rails at 80mph, along a curve south of Seattle, killing three and injuring dozens.

Authorities have revealed that Gran, who was autistic and a huge train enthusiast, was a registered sex offender who was sentenced to a lifetime of supervised release after he was caught with a massive amount of child pornography.

Convicted sex offender Benjamin Gran, (pictured) 40, of Auburn, Washington, died of multiple traumatic injuries on Monday when the Amtrak Cascades train 501 plummeted off the rails at 80mph, along a curve south of Seattle, killing three and injuring dozens

Gran was working as a computer technician at Auburn's Green River Community College, Washington, in 2011 when an investigation identified him as a member of an online pedophile ring.

The probe, dubbed 'Operation Rescue', began in the Netherlands in 2009 but stretched on for years, and across different countries, and ultimately saw 12 suspected child abusers arrested and rescued 100 children.

Agents from the US Department of Homeland Security and Dutch police visited Gran's home in 2011.

The investigation found that Gran had been in communication with the ringleader Robert Mikelsons since 2004 who had claimed the sexual abuse was good for the children, according to court papers.

He was placed on paid administrative leave for months until he pleaded guilty and served two years in prison before his release in 2015. He was also ordered to register as a sex offender.

Gran was among the three passengers who died on the maiden voyage of a faster train route between Seattle and Portland, Oregon.

While his family conceded that Gran had a past, his mother Linda Daniels told Seattle Pi her son had recovered from his 'little blip' and had made a new life for himself.

She described the 40-year-old as her 'autistic, but awesomely autistic son' who was passionate about trains.

He 'was an Amtrak fan to the max,' she added.

Daniels said his death 'left his friends and family shattered beyond belief.'

Local transit employee Zack Willhoite (left in an undated photo) and his friend Jim Hamre (right) were also killed in the crash

The train derailed on Monday and several cars were sent plummeting onto the interstate below

Train enthusiasts Jim Hamre, 61, and Zack Willhoite, 35, died of severe brain and skull injuries from blunt impact on the train. Dozens of others were hurt, some seriously.

Both men belonged to the rail advocacy group All Aboard Washington and were excited to be on board for the inaugural run: Hamre, a retired civil engineer with the state Transportation Department, and Willhoite, a customer service employee at a local transit agency.

'It's pretty devastating. We're having a tough time,' said All Aboard Washington executive director Lloyd Flem.

Willhoite, 35, and friend Hamre were both killed when the train careened off an overpass south of Seattle, spilling cars onto the highway below on Monday. The third victim has not yet been identified.

Friends of the two identified victims say they had just wanted to be among the first on the train's maiden journey.

The engine from the Amtrak train crash onto Interstate 5 two days earlier is checked by workers before being transported away from the scene, Wednesday

A cloud of smoke billows out as a transport vehicle carries the engine from an Amtrak train that crashed onto Interstate 5 on Wednesday

People work at the curve where an Amtrak train derailed onto Interstate 5 two days earlier Wednesday

A damaged Amtrak passenger train car is lifted from the tracks at the site of the derailment of an Amtrak train in Dupont on Tuesday

Willhoite had worked at the Washington-based Pierce Transit since 2008. Hamre previously worked for the Washington State Department of Transportation and was involved in the Washington Association of Railroad Passengers.

'It's heartbreaking to hear that @PierceTransit employee and rail aficionado Zack Willhoite did not survive the derailment,' chair of the transit company's advisory board Chris Karnes tweeted on Tuesday.

'He helped our advisory committee with IT issues, and behind the scenes he was a writer and advocate for better transit for all. He will be missed.'

A friend paid tribute to both men on Hamre's Facebook page, saying: 'As we all knew they would be, Jim and his great friend Zach Wilhoite were on Amtrak Train 501 on the first run over the new route and they were, unbelievably, two of the three killed in the horrible derailment of that train.'

Authorities are investigating the wreck and have said that the train was going 80 mph in a 30 mph zone, derailing south of Seattle and toppling some cars on Interstate 5 below.

Officials have revealed that a second person was in the cab during the deadly Amtrak crash- as investigators look into whether they may have distracted the driver. Pictured: the derailed train dangles over the edge

Local officials had voiced their concerns about the train speeding so fast through bends at a meeting earlier this month

A few motorists were injured when none of the cars came falling down onto the road, but none were killed

National Transportation Safety Board member Bella Dinh-Zarr has revealed that not only was the train going 50mph above the speed limit, but its emergency brakes only deployed automatically as the fatal derailment occurred. The driver never braked during as he sped round the curve.

'When there is an accident, the emergency brake system goes to place,' she told Buzzfeed. 'It was not something the engineer actually initiated himself.'

One factor that could have potentially slowed down, or even avoided the crash altogether would have been critical speed-control technology. But instead of waiting until the safety system was installed and certified, Amtrak decided to open the new route without the positive train control.

A positive train control system could have detected the speeding and automatically applied the brakes to stop the train, said Najmedin Meshkati, a University of Southern California professor who has studied the technology for three decades.

'It is another layer of safety,' he said.

Dinh-Zarr said it is too soon to say whether positive train control would have prevented Monday's tragedy.

Investigators with the NTSB arrived on the scene of the derailment late Monday night

First responders work at the scene of an Amtrak train that derailed in DuPont, south of Seattle on Monday,

Two semi trucks were damaged in the early Monday morning derailment, in addition to five cars

Work to install the sophisticated, GPS-based technology isn't expected to be completed until next spring on the newly opened 15-mile span where the train derailed, according to Sound Transit, the public agency that owns the tracks.

Amtrak and the Washington Department of Transportation started publicizing the switch to the new route in October. Amtrak CEO Richard Anderson said that 'no one wants PTC more than me' but would not directly answer questions about why it is taking so long to get the speed-control technology up and running across the board.

Passengers described the crash as 'like being in an exploded bomb' after the train ran off the rails at 80mph along a curve south of Seattle - sending some of its cars plummeting onto an interstate highway below.

National Transportation Safety Board member Bella Dinh-Zarr said it is not yet known what caused the train to derail and too early to say why it was going so fast.

An investigation is still underway and investigators are speaking to the engineer and other crew members, but it is standard procedure to look at whether the engineer was distracted or incapacitated.

The engineer, whose name was not released, was bleeding from the head after the crash, and his eyes were swollen shut, according to radio transmissions from a crew member. The transmissions mentioned a second person in the front of the train who was also hurt.