Was there an assassin on Grant's train?

[Eva Elisabeth]

My opinion - she embellished a bit to provide more "drama" to the reader, also time expands memory, and people tend to believe these expanded versions. Like a proud hobby angler's caught fish gets bigger and bigger over the time.
Why didn't she tell of this incident instantly? Even if not for the purpose of investigation, but in letter or orally to friends. I would think most people wouldn't have kept such a "thrilling" account by themselves for decades. Despite I would think her eyesight might have made it difficult to identify those strangers later.