The New Zealand E class battery-electric locomotive represented the third unique type of locomotive class to be given the E classification in New Zealand. The first was the E class of nine Double Fairlie steam locomotives of 1872-75; the second E class consisted of a Mallet compound made in 1906; and as both were no longer operated by the New Zealand Railways in 1923, the classification was free to be used for a third time when the small battery-electric locomotive was delivered. This is the only time a classification has been used three times in New Zealand, though re-use happened a number of other times, arguably most notably when the A class of 1906 took the designation originally used by the A class of 1873.