Normal Direction of Travel
The Normal Direction of Travel (sometimes called NDOT)determines the direction and operation of lighting.
Changing the CV that controls this feature will reverse the locomotive's direction of travel. Early diesels were constructed with the cab at the front (cab units, such as the EMD F and E series, the ALCO PA/FA, and FM's C-Liners). With the appearance of the hood units (EMD's GPs, or FM's Trainmaster), many railroads opted to run them long hood forward, with the engineer and fireman in the cab toward the rear, like a steam locomotive, for crew safety. Later many were converted to short hood forward for visibility.
The NDOT would be used to determine long or short hood forward. The alternative to this CV would be to reverse the motor connections.
This feature is contained within CV 29, but not all decoders include this feature.