During a visit to the workshop the driving axle was incorrectly fitted by mistake, with the result that the locomotive ran backwards through the wall of the shed during the ensuing test run.
NEBEL was retired in 1890, whilst SCHWAAN continued in service until 1898 and from 1895 carried the number 3.
On HULDA the firebox extended under the trailing axle by means of a sloping base in order to achieve the greatest possible grate area.
Apart from MARSCHALL VORWÄRTS which had a conical chimney, all the engines had long cylindrical smokestacks.
On the SCHWAAN and the NEBEL the cylinders were angled and attached to the smokebox, the valve gear was external as well.