The first attempt from the resistance was Operation Grouse in October 1942, but failed and caught by the Germans; as a consequence passenger transport after 7 April 1942 from Ingolfsland Station to Rjukan was only permitted for soldiers, police, workers at the plant and schoolchildren. All filled ammonia wagons were stored indoors in a tunnel with heavy guarding. On 16 November 1943 the US Army Air Forces bombed the hydrogen plant; the attack killed 21 civilians but failed to touch the plant itself, located underneath seven stories of reinforced concrete. The secondary targets of the attack were the station at Rjukan, the industrial tracks and the track to Vemork. The attack caused great damage to the railway with locomotives No.7 and 8, eight cargo wagons and seven passenger wagons suffering damage. Total costs for the bombings were NOK 245,611, most of it related to rolling stock.