Ken Tranter wrote:Have just collected a very large cannon used at the battle of Waterloo and taken it to the new museum under construction there in readiness for the 200th anniversary of the battle. I noticed at Fort Nelson in Portsmouth a railway mounted gun and I was told that it was the one that was used in Dover during the 1939-1945 conflict. Apparently it was hidden in the Shepherdswell Tunnel between firings. Perhaps one of our local historians could enlighten me.
Cannot claim to be a local historian but think I have found the answer to Ken's intriguing question, see link below.
http://www.victorianforts.co.uk/art/sleigh.htm
There is a very interesting edition of "After the Battle" magazine (No.29 Cross-Channel Guns) which contains a lot of relevant info, summarised below.
In addition to some smaller rail mounted guns, four railway mounted guns from the First World War were deployed in Kent at the start of WW2 to combat the threat of German invasion. Had the Germans landed, then they would have fired on the invasion beaches and on road junctions from Ramsgate to Folkestone. Each consisted of a complete train consisting of the gun truck, ammunition trucks, accommodation coaches, etc, and was manned by a very large crew. Three of the rail mountings were fitted with 13.5 inch gun barrels from WW1 battleships and named Scene Shifter, Piece Maker and Gladiator. These were manned by the Royal Marines Siege Regiment.
It is the fourth WW1 railway gun that is the one in question. This was named Boche Buster and was mated with an 18 inch barrel, see bottom two photos above. It arrived at Bishopsbourne Tunnel in February 1941 and was manned by the 11th Super Heavy battery of the Royal Artillery. Fortunately, the invasion never transpired and it was never called upon to go into action. It did not have the range to fire across the channel so was never used against the German batteries on the French coast.
The mounting displayed at Fort Nelson is a railway proof sleigh used for test firings of gun barrels and is a much smaller animal than the railway mounted truck used for Boche Buster. The 18 inch barrel is one of four which were produced since barrels used to wear out after a few dozen shells had been fired. Whether it is the one which was actually installed on Boche Buster I am unsure. The proof sleigh certainly has a connection with Dover as it was used for test firings on the Isle of Grain of the barrel for the hyper velocity gun named "Bruce" which had an 8 inch barrel sleeved inside a 16 inch barrel with a breech enlarged to take a 13.5 inch cartridge giving it a range of seventy miles. Bruce was installed at St. Margarets and was used for test firings towards Shoeburyness but never used in action..