Set into an isolated section of concrete of approximately 1,200 square yards area, secreted away behind a business park in Gravesend, a rather complex array of standard gauge railway points can be found. Just fifty yards north of these rails, a redundant pier, stretching 150-feet into the Thames, still carries an impressive formation of tightly-curving railway lines, albeit hidden from general public view. These, in addition to a couple of office buildings, are the last remnants of the Imperial Paper Mills, an enormous operation once sandwiched in-between the Thames and the long-gone branch line to Gravesend West.
In 1909, the "Imperial Paper Mills, Ltd." company was formed by the newspaper and comic publishing giant "Amalgamated Press, Ltd.". The Amalgamated Press was registered on 1st January 1901 as the umbrella organisation to several publishing operations owned by one Alfred Harmsworth, a prominent figure in the British press who had published his first magazine in 1888, acquired his first newspaper title the "London Evening News" in 1894, and launched the "Daily Mail" title in 1896. The raison d'être of Imperial Paper Mills, Ltd. was to commission a huge works dedicated to the production of newsprint from pulp for Harmsworth's business.
The site chosen for the paper mills was that of a lime works, situated on the southern bank of the Thames in Gravesend. The works belonged to local cement-making firm "Tolhurst & Sons, Ltd", which had been at the site since at least the mid-1860s. Alfred Tolhurst owned a number of quarries in the area and on 25th December 1897, entered into a contract with the local Imperial Portland Cement Company to supply the latter with at least 750 tons of chalk per week for the subsequent fifty years. The works of Imperial Portland Cement was located half a mile west of Tolhurst's Gravesend pit, in Northfleet. The Imperial company was absorbed into the Associated Portland Cement Manufacturers (APCM) on 1st January 1900 and the Northfleet operation was closed by their successor in 1908.
The Imperial Paper Mills were opened in 1911, having been constructed and equipped in fifteen months. The site extended along the edge of the Thames for 1,200-feet and had the capacity to produce 1,500 tons of newsprint a week. A series of huge pitched-roof brown-brick buildings rose from the former lime works' site, these of which were linked by an extensive network of tightly-curved standard gauge railway lines. The latter were straddled at various points around the mill by a network of travelling cranes; these ran on rails elevated upon lattice struts and were used to stack bales of pulp into rows outside of the main buildings and to load/unload railway wagons. From the outset, the Imperial Paper Mills' railway was afforded a single-track inclined trailing connection with adjacent SE&CR branch line at Gravesend West Street station. As a result, any goods movement between the branch line and mills required a reversal manoeuvre onto the SE&CR's pier.
Given the flammable nature of paper, the hot ash of the traditional steam locomotive posed a fire risk at mills. A novel solution to this was the development of the "fireless" locomotive, which lacked a boiler and firebox and, instead, was equipped with a cylindrical reservoir. Steam would first be generated and pressurised in a static boiler and, through a pipe, then be pushed into the fireless locomotive's reservoir - the rest of the mechanics, such as pistons and connecting rods, were as per a standard locomotive. In the early 20th Century, Germany was a world leader in fireless locomotive construction and the country's first examples were made some years before manufacturers in Britain started to produce such machines. The Imperial Paper Mills ordered two fireless locomotives from German company "Orenstein & Koppel", the first (Works No. 4708) arriving in time for the mills' opening in 1911, the second (Works No. 5900) coming in the following year. These were distinctive locomotives, not only for the fact that they possessed a reservoir and not a boiler, but also given that their pistons were rear-mounted underneath the cab. The latter gave the impression that the chassis had been constructed back-to-front. Orenstein & Koppel had earlier produced a fireless locomotive in 1906 for the Empire Paper Mills, Greenhithe, situated 2¾-miles to the west.
The first British manufacturer of fireless locomotives was Andrew Barclay Sons & Company, Ltd of Kilmarnock, Scotland, which started producing these engines in 1912. The company built several of these locomotives during World War I when, of course, it was no longer possible to source them from Germany. The Imperial Paper Mills initially ordered two of these from Andrew Barclay, the first (Works No. 1471) arriving in Gravesend in 1916 and the second (Works No. 1496) being delivered in 1917. These engines possessed cylinders of 15-inch diameter, had an 18-inch stroke, and their reservoirs were charged with steam to a pressure of 160lbs per square inch from a static boiler of 165lbs per square inch pressure. The arrangement was of the 0-4-0 type, the wheels being 3-feet in diameter and the wheelbase extending to 6-foot 6-inches.