Colonel Wethered further communicated to The Times of May 25, 1877, a letter on "Portable Batteries" in which he declared that if, before an enemy could effect a landing, we were to provide the means of concentrating, with unerring certainty, on any given points of the coast, a crushing force of artillery, with guns of heavier calibre than even the warships of the invader could command, it would be impossible for the vessels of an invading force to approach near enough to effect the landing of their men. He continued:—
My proposal is to take the full advantage which our railway system, in connection with our insular position, affords, and provide powerful moveable batteries which can be sent fully equipped in fighting order direct by railway to any required point; and the recent experimental trials of the 81-ton gun have proved that the heaviest ordnance can be moved and fought on railway metals with considerable advantage.... In connection with our present main lines of railway, which probably would require strengthening at certain points, I would construct branch lines or sidings leading to every strategical point of our coast and into every fort, as far as possible, with requisite platforms.... These branch lines during peace would, doubtless, be of some small commercial value.... I would mount as many of our heaviest guns as practicable on railway gun carriages so that they could be moved by rail from one face of a front to another, and from one place to another.
He also recommended that guns thus mounted, fully equipped, and ready for use, should be kept at three large central depôts which might be utilised for the defence of London. At each of them he would station (1) Militia and Volunteer Artillery able not only to work the guns but to construct, repair or destroy railway lines, and (2) a locomotive corps specially trained in the working of traffic under war conditions.
By reading a paper at the Royal United Service Institution on April 24, 1891, on "The Use of Railways for Coast and Harbour Defence,"[13] Lieut. E. P. Girouard, R.E. (now Major-General Sir E. Percy C. Girouard, K.C.M.G.), made what was, at that time, an important contribution to a subject on which there was then still much to be learned. Sketching a detailed scheme comprising the employment of all the coastal railways for the purposes of national defence, he emphasised the value of Britain's "enormous railway power" as the strong point of her defensive position, whether regarded from the point of view of (1) railway mileage open as compared with the square mile of coastal area to be defended, or (2) the length of coast line compared with the railway mileage at or near that coast line, and, therefore, locally available for its defence. "Why," he asked, "should we not turn to account the enormous advantage which our great railway power gives us to concentrate every available gun at a threatened point in the right and the proper time, which the proper utilisation of our railways can and will do, thereby practically doubling or quadrupling our available gun power?"
Whilst the subject had thus been under discussion in the United Kingdom, America, in her Civil War of 1861-65, had set the rest of the world an example by actually introducing armoured-protected gun-carrying trucks into modern warfare.
Writing from Washington, under date August 29, 1862, to Colonel Herman Haupt, then Chief of Construction and Transportation in the Department of Rappahannock, Mr. P. H. Watson, Assistant-Secretary of War, said:—"An armour-clad car, bullet proof, and mounting a cannon, has arrived here and will be sent down to Alexandria." A later message, on the same date added:—"After you see the bullet-proof car, let me know what you think of it. I think you ought at once to have a locomotive protected by armour. Can you have the work done expeditiously and well at Alexandria, or shall I get it done at Philadelphia or Wilmington?" The car was duly received; but Haupt's comments in respect to it, as recorded in his "Reminiscences," show that he was not greatly impressed by the innovation. "P. H. Watson, Assistant-Secretary of War, sent me," he says, "an armour-clad, bullet-proof car, mounting a cannon. The kindness was appreciated, but the present was an elephant. I could not use it, and, being in the way, it was finally side-tracked on an old siding in Alexandria."
It would seem, however, that other armour-clad cars were brought into actual use during the course of the Civil War.
In the Railway Age Gazette (Chicago) for January 22, 1915, Mr. Frederick Hobart, associated editor of the New York Engineer and Mining Journal, writes, from personal knowledge, of two armoured cars which were in use in the Civil War. One of these, formed by heavy timbers built up on a flat car, was put together in the shops of the Atlantic and North Carolina Railroad Company at Newberne, N.C., in 1862, about two months after the city had been captured by the Burnside expedition. The armour consisted of old rails spiked on the outside of the planking composing the sides and front of the car. Along the sides there were slits for musketry fire, and at the front end there was a port hole covered with a shutter behind which a gun from one of the field batteries was mounted. The second car was similarly constructed, but was armed with a naval howitzer. The cars were run ahead of the engine, and were used in reconnoitring along the railroad line west of Newberne. Mr. Hobart adds that he was quite familiar with the cars, having assisted in the design and construction of both.