A little obsessive perhaps, but I wouldn't say abnormal. Definitely more normal than collecting, say, lunch boxes or toasters. i actually had a boss once who collected TOASTERS. I asked her about it once, and she launched into a misty-eyed speech about the favorites in her collection and the ones that continued to elude her grasp. Somehow, checking locomotives or songbirds off of your list seems more normal to me.
As far as headphones go, I always find myself trying to identify the cans people are listening to as they walk by on the street. This elicits the occasional hostile glance, but it doesn't seem terribly abnormal to me. Perhaps the people who think I'm staring at them would disagree
. But it's also led to some cool conversations. I stopped a guy on a subway platform once because he was wearing SR-60s, and I was interested in his opinion of them. We ended up talking for a couple of minutes, and comparing notes on different phones we've tried.
As the saying goes, one man's ceiling is another man's floor.