Known as "Pet" at the erstwhile Agwi refinery at Fawley, this is a two cylinder petrol locomotive built by Motor Rail Ltd. of Bedford and sold under their "Simplex" trademark. By 1939, when she was made, most of these machines were being fitted with diesel engines and the archaic power unit ideally needs its own refinery to keep it in fuel! Modified by the addition of a cab and alterations to the ignition system, Agwi now performs valuable service at Bursledon on permanent way trains and on the demonstration runs for visitors.