DENVER -- "I just hit a car crossing through Chambers crossing," the engineer said, his voice shaking, as he radioed for help following Monday morning's deadly train crash.
For rail workers, it has become a devastating part of the job.
Advocates say, on average, train operators will face three traumatic incidents over a 25-year career.
"It's just not something that you're ever prepared for," said John Tolman, the Vice President of the Brotherhood of Locomotive Engineers and Trainmen. "You're typically the last person to see that previous person alive, so needless to say, it's traumatic."
An engineer in Boston for more than 25 years, he vividly remembers a day in 1986 when his locomotive struck a car, killing the person inside.
"We always believed it was a suicide, unfortunately," said Tolman. "You'll never ever in your entire life forget an incident that you've gone through. It's in slow motion, and you never forget."
In 2013, the National Transportation Safety Board reported 891 rail deaths, and research shows a major impact on rail workers.
A 2011 study from the Transportation Institute at the University of Denver states that nearly 44% of those rail workers surveyed were involved in at least "critical incident," and many of those reported PTSD symptoms, sleep issues and depression.
While railroads are required to provide time off and mental health assistance after accidents, advocates said more can be done, such as required paid time off.
In the meantime, they try to prepare operators for inevitable tragedy.
"It's not an easy thing, it's not a part of the job that we signed up for, but it's part of the reality," said Tolman. "People think it's an easy way out, but it's not fair."