When I speak to Dr. Alan, there is no option to speak about the train crash ailment. All I can do is buy medical supplies or pay for treatment. Am I missing something?

That's what I thought as well. Instead he cured the Ferryman who sent me on to the next objective. So, either it's bugged or the cure will come later. Currently on my way to find Lazarus, so maybe he will cure me?
Also, I couldn't find any further hints when I ins´pected the quests in the console. It seems to be the only quest I could not see in the list of active quests and thus I couldn't get a list of steps for that quest.

Same here but it doesn't seem to affect overall health, so I'm wondering if it's a quest item which has no bearing on the game. It would be good to know though