Ed,
In a quick search on the cars on Google (I have the original 2 car set from the RTR set. As far as I'm concerned, the RTR set was produced and a 2 car dummy add-on) to try to answer your question I came across this...
In April of this year you posted the following:
"Brand new in sealed set box and box with the 2 car add-on car set. The catalog number of the set is 30-4122-1 and the 2 car add-on car set is 30-2417-3. The price for both the set and the add-on car set is $500.00. The set was produced about 10 years ago for the Yankees-Mets World Series of 2000."
Judging by this, I'd say you may know the answer already . The set I have is a very nice set. I rarely take it out of the boxes, as well, I'm not a baseball fan, nor do I really care for electrics and subways. I think the sounds are neat with the city "background" noise and automatic start/stop features.