In the mid-90s, Norfolk Southern didn't want increasingly high-horsepower locomotives, nor did they want wide noses. GE satisfied their request with the C40-9 (Dash 9-40C), the last standard-nose engine GE produced. Its most obvious distinguishing feature from the C40-8 it replaced are its high-adhesion (known to some railfans as "rollerblade") trucks. http://users.thot.net/lalande/jamesleo/dash9trk.htm High adhesion truck http://railpictures.net/viewphoto.php?id=160026 Left side http://railpictures.net/viewphoto.php?id=162429 Right side After the C40-9, NS finally ordered its first widenose engines. (Deliveries of standard-nose SD70s would continue for some time.) They still didn't want the higher horsepower of the C44-9W, so GE built the C40-9W. The C40-9W can only be distinguished from the C44-9W by its headlights. The C40-9W has cab-mounted headlights, while the C44-9W has nose-mounted headlights. http://www.railpictures.net/viewphoto.php?id=163674 C40-9W nose http://railpictures.net/viewphoto.php?id=158970 C44-9W nose for comparison http://railpictures.net/viewphoto.php?id=158877 C40-9W and C44-9W http://www.railpictures.net/viewphoto.php?id=162992 NS The C40-9W was replaced by the ES40DC.