Normal Direction of Travel
Summary: The Normal Direction of Travel or NDOT determines the direction and operation of lighting. It is Bit 0 of CV29 and is usually set to 0 (Off).
This feature is contained within CV 29, but not all multifunction decoders include this feature. Changing CV 29 (Bit 0, Direction) will reverse the locomotive's direction of travel and lighting effects.
Early diesel locomotives were constructed with the cab at the front (cab/carbody units), such as the EMD/GMD F and E series, the ALCO PA/FA, and FM's C-Liners. With the appearance of the hood units (ALCO's RS series, EMD/GMD GPs or FM's HH series such as the Train Master), 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 better visibility.
The NDOT bit of CV29 is often used when consisting locomotives for multiple unit operations. The command station usually makes these changes as needed during the consisting process. This allows proper operation of the forward lighting.
If the motor was mis-wired resulting in the wrong direction of travel, the proper solution is to reverse the wires. The NDOT bit may be used for something else, and altering it unnecessarily could create problems later.