Not really a bump but more of an emphasis of the "ghost" trains - the ones that just coast real quiet like with the engine seemingly off. It happened that in this particular large, active yard that two lines were moving at the same time. The first I noticed was going quickly and making a great deal of noise. Because of this I neglected to notice the line right behind me roll right on past very close to me. I swear I didn't hear it or feel it. I nearly shit myself. I guess I would have to say that I wasn't on 100% alert. Could have killed me I bet.
