In spite of the small superheater area, problems arose with the slide valve on the low-pressure side. As a result, the following 126 engines were supplied with piston valves on both sides (429.100–429.225). At the same time a two-cylinder simple variant with piston valves was tried, of which in the end 197 units were procured by the kkStB (429.900–429.999 and 429.1900–429.1996).
The 429s were employed for all duties and with good coal generated up to 1,200
PS (883
kW; 1,180
hp).
They were to be found in almost all parts of the
Danube Monarchy.
After the
First World War the former 429s became Class 354.7 with the
ČSD, Class Ol12 in the
PKP, Class 106 in the
JDŽ, Class 688 in the
FS and were also used by the
Romanian State Railways retaining their original numbers.
A total of 87 units (46 compound, 41 two-cylinder locomotives) remained in the
BBÖ. The six Südbahn locomotives came to the MÁV, which gave them the designation 323.901–323.906. In addition, the ex kkStB 429.116, which had gone to the PKP as Ol12-24, went to the MÁV as 323.907, the number of which was later changed to 323.908.
In 1939 the
Deutsche Reichsbahn (DRB) reclassified the simple engines as 35 201 – 35 241 and the compounds as 35 301 – 35 346. During the course of the war, several locomotives from the ČSD and JDŽ ended up in the DRB. After the
Second World War 46 simple locomotives were left in the ÖBB and became their Class 35, as well as 39 compound engines which became Class 135.
The serial numbers were not changed from those allocated by the DRB.
ČSD Class 354.7
The
ČSD in Czechoslovakia converted all its compound locomotives (27 of the first series, 57 of the second) into two-cylinder engines.
Together with the 68 two-cylinder machines taken over, they therefore had over 152 examples of Class 354.7.
With the exception of one engine, all the locomotives were give a second
steam dome with a connecting pipe.
The ČSD did not withdraw Class 354.7 engines from its fleet until 1967.