E3703 started life as a wooden bodied insulated meat wagon W606 built in 1934. In 1964 it was rebuilt to its current form. That involved removing the wooden body and floor and fitting a steel tank . The wheels were also fitted with package roller bearings. In this form 3703 was mainly used for the transport of creosote from Gas Works to Sleeper treatment plants before being withdrawn in the 1990s and stored for several years at Hutt shops before being obtained by SSR in 2002. It is currently used to store fuel for Ka 935.