207 is a Long Tom type carriage, fitted with longitudinal seating and two lavatories. It was constructed at the South Australian Railways' (SAR) Islington workshops and entered service on 18 December 1914.
207 saw extensive service on the Peterborough Division of the SAR until it was transferred to the Port Lincoln Division on 4 November 1954 after extensive modifications.
The Long Tom name came about because it is a long carriage, at least compared to the Short Tom cars. A Long Tom is approx 50 feet (15.25 m) long over the body, while a Short Tom is approximately 30 feet (9.15 m).