In the 1930s the company manufactured narrow gauge steam outline diesel-hydraulic locomotives for use at amusement parks around the country. In 1931 "Neptune" was delivered to Scarborough North Bay Railway, followed a year later by "Triton", both being gauge. In the same year they supplied a "Robin Hood" to Golden Acre Park in Leeds followed by a 4-6-2 "May Thompson" in 1933. They also supplied "Mary Louise" and "Carol Jean" to Blackpool Pleasure Beach for use on the gauge Pleasure Beach Express in 1933. A fire in 1934 badly damaged "Carol Jean" so "Princess Royal" was ordered as a replacement. They went on to build two more class locomotives, "Princess Elizabeth" and "Princess Margaret Rose" for Billy Butlin to use at the Empire Exhibition in Glasgow in 1938 which were then transferred to his holiday camp in Clacton when the exhibition closed.