Most if not all road switcher/hood unit diesel locomotives have the cab offset towards one end of the unit, with a hood at each end; thus, one hood is the long hood and the other is the short hood. Either of them could be designated the front end: although in recent years the short hood is pretty much universally designated the front, in the early days many railroads designated the long hood as the front, with the cab at the rear in steam locomotive fashion.
On most locomotives the long hood is full height. It contains the diesel prime mover, the main generator, auxilary generators if any, the radiators and their associated fans, the dynamic brake equipment if fitted, and on some locomotive designs a steam generator for providing heating for passenger cars.