From left to right:
Older Lionel Chessie System GP20
K-Line Hauler
Lionel Semi
1:50 Beer Truck
1:43 Chevy (Eastwood)
1:43 Chevelle
Personally in this picture, I think the K-Line looks a lot better than the Lionel. I think it mixes well with the 1:43 cars and the train.