I vaguely remember the Silverliner II's and III's had a "unique" smell to them when my mom took me on my first few train rides in the late 1960's/early 1970's. I'm not sure if they've pretty much maintained the same smell over the years. From the mid 1980's through the 1990's, which was my "peak" railfanning period, the Silverliner II's, III's and IV's (with the old interiors) smelled almost the same...at least not much noticeably different from each other. Of coarse, when the IV's had their interiors redone they had the "new car smell" for a while and I'm sure the airport III's had somewhat of a "new" smell to them when they were overhauled with the new seats. I've been on the airport III's only a couple of times and never really took notice of what they smelled like.
You take the midnight subway train...You're calling all the shots...You're struck by lightning...You're in love. RATT, 1985