This is my first post on the forum.  Have grown up collecting lionel trains and thankfully have a fiance that likes and tolerates my growing collection.   I recently ended up with what I thought was a General Mills Era Southern A B A engine set.  They were in the General mills era orange boxes.  Turned them over and saw Lionel LLC in the casting on the bottom and very modern toggle switches and electric couplers.  Inside I found railsounds and TMCC.  I have not been able to find a locomotive quite like this one in any Lionel LLC Catalog.   The shells look like they are from the General Mills Era but have open port holes and grab bars on the front.   The horns are plastic from the General Mills Era.  I have added a link to the images of the one A unit below.  All I can figure is someone swapped the shells onto a more modern chassis.

http://imageshack.com/a/img844/7764/atz9.jpg
http://imageshack.com/a/img839/2234/mvh9.jpg