It is opinion type question. The question is really- "Is there anything that the Allies could have done to slow down or stop the holocaust?" The Allied leadership, at the time, felt that the best way to end the mass murder, was to quickly defeat the Germans (& their allies). Sending aircraft & crews on missions to death camps would have diverted resources from ending the war, those prolonging the weeks & months that the death camps could operate. Bombing the death camps would have killed the people you are trying to save. The death camps would be repaired and back in operation in hours. It is very unlikely that bombing the rail lines leading to the death camps would have prevented the holocaust. British & American aircraft flying from England or Italy would have been at the limits of their range to reach these targets in eastern Europe. Damage to roads & railroads by bombers was only temporary. They could quickly be repaired by the Germans, especially by using all that slave labor from the nearby death camp. In any event that a particular death camp could have been cutoff from the transportation network, the Germans could have diverted the targeted population (primarliy Jewish people) to any number of other death camps. Top Nazi leaders issued orders that gave a vey high priority of effort to the holocaust work, even a higher priority than winning the war. What options did the allies really have, short of winning the war quickly? Possibly a campaign (leaflets, radio broadcasts, etc. ) to inform the German people about the holocaust? Would the Germans believe their enemy or their leaders? If they believed, what could they do? Would the Nazis have accelerated the genocide program once they knew that the Allies were aware of it? The allies could have diverted more resources to target railroads and other transportation lines throughout all occupied Europe? Would that have really been practical and actually achieve any beneficial results? My opinion-not likely. Unfortunately, the Allies were unable to determine a specific course of action that had a good chance of success to deal specifically with death camps.