In 2006 , the Nihonkai sleeping car service no longer ran through the tunnel .
JR Freight also ceased using JR Hokkaido locomotives on freight services , due to the increased availability of Class EH500 locomotives .
In 2006 , the Nihonkai sleeping car service no longer ran through the tunnel , and JR Freight also ceased using JR Hokkaido locomotives on freight services , due to the increased availability of Class EH500 locomotives .