By the start of World War I, both the Queen Elizabeth-class and the Revenge-class battleships were partly oil-fired: oil was used mainly for both quick-start steaming, and sprayed on burning coal to extend their range. A number of cruiser and destroyer classes produced since 1904 also used oil. However by the time of the Battle of Jutland in May/June 1916 still only a sixth of the Grand Fleet was oil-fired. Further, that summer the British suffered a number of losses of oil tankers, and had to instruct oil-fired ships to restrict their fuel consumption and hence speed. When the United States entered the war in April 1917, the British instructed the United States Navy to send only coal-fired ships to assist them. To assist the Royal Navy, from the outset of the war the Government and railway companies ran what were termed "Jellicoe Specials", high-speed coal carrying freight trains that ran from South Wales to north-east Scotland, and then by ship to Scapa Flow. Initially running to Dingwall, they then were also shipped to Scrabster through Thurso. However, inadequate capacity in port and rail facilities at these locations meant that from January 1915, all naval ordnance (other than ammunition) and medical supplies were sent by rail to Aberdeen, and from mid-1915 Grangemouth. By the end of WWI, the Royal Navy had 33 dreadnoughts and 9 battle cruisers, with 10 and 2 respectively entirely oil fuelled.