One source states that a total of 2,800 cubic meters of soil was removed and 170 cubic meters of wood and 45 tons of steel were used in the construction of the tunnel. The biggest technical problem was the underground water, which had to be frequently thrown out manually. Because of the permanent shelling, the tunnel was installed with a pipeline that was used for the delivery of oil for the town. Communication lines and electric cables donated by Germany were also installed so that Sarajevo had electricity and telephone lines connecting it with the world.