Whereas the Auschwitz II (Auschwitz–Birkenau) and Majdanek camps were parts of a labor camp complex, the Chełmno and Operation Reinhard death camps (that is, Bełżec, Sobibór, and Treblinka) were built exclusively for the rapid extermination of entire communities of people (primarily Jews) within hours of their arrival. All were constructed near branch lines that linked to the Polish railway system, with staff members transferring between locations. These camps had almost identical design: they were several hundred metres in length and width, and were equipped with only minimal staff housing and support installations not meant for the victims crammed into the railway transports.