The evacuation transport, of which Willem Vos, among others, was part of, from the Auschwitz complex to the KL Buchenwald: from 21 January to 2 February 1945 on foot from Blechhammer, beloning to Auschwitz III, to the KL Gross Rosen and then on 7 February by train to the KL Buchenwald. Arrivals there on 9 and 10 February 1945.
Departure on foot on 21 January 1945 from the Aussen Kommando Blechhammer to the Konzentrations Lager Gross Rosen via Neustadt - Frankenstein - Stansee - Schweidnitz and Reichenau. Arrival at KL Gross Rosen on 2 February 1945. Then departure from the KL Gross Rosen on 7 February 1945 by train to KL Buchenwald via Liegnitz - Goerlitz - Dresden - Chemnitz - Gern - Jena and Weimar. Arrivals in KL Buchenwald on 9 and 10 February 1945.
Source: The Dutch Red Cross, The Hague, publication from March 1952, Auschwitz Part VI. The evacuation transports from Auschwitz and surroundings to the North and to the West and the large evacuation transports, page 146.
KL = Konzentrations Lager = Concentration Camp
AK = Aussen Kommando = Labor Command or Labor camp.