The longer the time between the accident and the date of filing, the more of a case he has to make on the agency denying him disability (which in this case, was three years).
But in this article, it says he wasn't given the proper equipment to operate with. Now if he's going about it in the way he was denied disability, the Railroad hated him that much that they didn't even give him a dime.
BUT, with an undiagnosed condition, you could also say it was something he failed to disclose so much that it could affect his job to the extent that he wouldn't be operating trains, thus affecting his income.
I will say this:
The sleep apnea thing that's been the main case of this and the recent accident in Hoboken, and because these engineers didn't take it upon themselves to get treatment, is now going to have a widespread effect on the transportation industry as a whole, bus ops, truckers, railroaders included (in a similar case, the crash in Chase, Maryland that killed 16 people and the Conrail engineer was found under the influence of drugs, thus ramping up drug and alcohol testing for all transit operators). It's already hitting the bus operators. I've known a few folks who have been put out until they do a sleep study.
In essence, the Federal government is now going to come out guns blazing and the after effect will not be pretty