Tom -- when I get around to replacing the nichrome wire, I'll take a look inside the engine shell. The set came with link couplers, but I somehow managed to badger my parents into having all the couplers replaced with knuckles when they came out (I think my line of argumentation was simply that if they were gonna continue to buy me new cars, etc., the new knuckle couplers wouldn't be compatible... probably wasn't that sophisticated!). The font on the tender is indeed serifed - American Flyer Lines with the PRR logo stamped in the upper 'near engine' corners. The 651baggage car and two 650 passenger cars are green. In an earlier attempt at identifying which set my first train set was, it looked to me like 4609A was pretty close except for the green color of the cars. Somewhere I read (or think I did) that sometimes the green color was used instead of the red. I don't recall getting track locks, but since I sometimes don't remember what I had for breakfast last week, I'm not sure that's reliable.
One thing I now realize is just how 'unreliable' the catalog art is in terms of the identification numbers on locos - as I just flipped through several of the older catalogs on Harrington's great website, myflyertrains. Its also interesting that after Gilbert's brief flirtation with the whistle in the tender (314AW - running afoul of Lionel's patent, IIRC), they went back to the 312 and 312AC for a year or so before introducing the next version.
