In 1846, the KFNB had six 4-2-0 machines manufactured by Günther in Wiener Neustadt, which were basically similar to the Norris locomotives from the USA. They were lighter than other machines previously made by European manufacturers. They were given the names “Adonis”, “Jason”, “Deucalion”, “Phaeton”, “Endymion” and “Ganymed”.
The “Jason” fell victim to a boiler explosion in 1848. The technical data given refer to the state after the boilers had been replaced on the other five locomotives between 1853 and 1865. After the “Adonis” had been retired in 1862, all others were retired in 1866.