Driver’s Eye Level (DEL)

The vertical distance between the driver’s eyes when in the normal, seated
position, and the crown of the Left-Hand Rail. (This may be a nominal
value, representative of several types of driving cab and/or the variation in
the population of drivers. Alternatively, for a particular scenario, it may be a
specific, measured value. Unless special circumstances dictate, driving
seats are assumed to be adjusted vertically to their mid-position.)