The class 18.5 express train locomotive belongs to the Bavarian S 3/6 family. The 18 537 would be delivered by Maffei as delivery series n. Due to the bankruptcy of Maffei, Henschel took over the construction and delivered the remaining 18 machines as series o. The last 11 machines - of which the 18 537 was the first - were delivered with a newly developed tender called 2'2' T 31.7.
Between 1953 and 1956, some locomotives of the series received a new boiler and were assigned to the series 18.6. The 18 537 did not receive a new boiler.
The locomotives were completely withdrawn from service between 1961 and 1965.
The operating condition of this locomotive is around 1958/59.