This is a Diesel locomotive from the 1977 No.5 manual adapted to run on O gauge track. This is seen pulling two tank wagons and two freight cars on a smaller O gauge track.The original model is meant to run back and forth on a straight track made from angle girders, but I have modified it to run on O gauge track and also pull four wagons (these are not part of the manual model). This model is powered by a meccano pdu motor and takes current from the track. The locomotive needed additional weight as it would not be able to pull the wagons and would become unstable and derail. The original model from the manual can be seen in the beginning of this video.