No.42 must have been considered successful because the NCC built another similar engine in 1914 in their own works at York Road, Belfast. This was numbered No.16 and for many years was nicknamed the "Donkey". In many ways it was a replica of No.42 and with similar leading dimensions except that throughout its life a cab was fitted, recessed at the spectacle plate to allow for the safety valves, which in this case were of the Ross "pop" type. The spectacles were larger than those of No.42 and rectangular rather than round.