As Chip rightly says, the whole business of the Train in WW1 is complicated to say the least. For all intents and purposes the peacetime Train-Abteilungen ceased to exist at mobilization forming a myriad of Provisons Columns, Field Bakeries, Horse Depots and slaughter house detachments etc. Originally the various columns were permanently attached to Corps and Divisions but with the increasing demand on transportation, it became impractical to move a Division's Train elements every time a Division was rotated to a different sector or front. Consequently at the end of 1916/early 1917 all the Train elements were removed from Corps and Divisional control and became static, supporting newly in-place formations as they were rotated into the front line. The train formations (Columns) were then numbered consecutively whose numbers bore no real relationship to their original Train-Abteilung or corps/Division affiliation. With effect 21 April 1917 shoulder straps of Potash-blue with red numbers were introduced for Prussian Train Columns.
Therefore, one has possible units with the number 146 as follows:
Proviant-Kolonne 146
Fuhrpark Kolonnne 146
Etappen Fuhrpark-Kolonne 146
Magazin-Fuhrpark-Kolonne 146
Feldbäckerei-Kolonne 146
Etappen-Bäckerei und Hilfsbäckerei-Kolonne 146
Feldschlächterei-Kolonne 146
At this moment in time, the published literature is not available that details which original formations formed which column. Again as Chip points out, hopefully Jürgen Kraus will address this gap.
I have identified Feldbäckerei-Kolonne 146 as being a component of Heeresgruppe Linsingen in March 1918.
Regards
Glenn