Armstrong was then Engineer of Rifled Ordnance for the War Office and the company's main customer was the British Government. Armstrong held no financial interest in the company until 1864 when he left Government service, and Elswick Ordnance was reunited with the main Armstrong businesses to form Sir W.G. Armstrong & Company. EOC was then the armaments branch of W.G. Armstrong & Company and later of Armstrong Whitworth. Elswick Ordnance was a major arms developer before and during World War I. The ordnance and ammunition it manufactured for the British Government were stamped EOC, while guns made for export were usually marked "W.G. Armstrong". The 28 cm howitzer L/10 which played a major role in the Siege of Port Arthur in the Russo-Japanese War was developed by Armstrong. Locomotives After the Great War, Armstrong Whitworth converted its Scotswood Works to build railway locomotives. From 1919 it rapidly penetrated the locomotive market due to its modern plant. Its two largest contracts were 200 2-8-0s for the Belgian State Railways in 1920 and 327 Black 5 4-6-0s for the LMS in 1935/36. AW also modified locomotives. In 1926 Palestine Railways sent six of its H class Baldwin 4-6-0 locomotives to AW for conversion into 4-6-2 tank locomotives to work the PR's steeply graded branch between Jaffa and Jerusalem. PR also sent another six H Class Baldwins for their defective steel fireboxes to be replaced with copper ones. AW's well-equipped works included its own design department and enabled it to build large locomotives, including an order for 30 engines of three types for the modernisation of the South Australian Railways in 1926. These included ten 500 class 4-8-2 locomotives, which were the largest non-articulated locomotives built in Great Britain, and were based on Alco drawings modified by AW and SAR engineers. They were a sensation in Australia. AW went on to build 20 large three-cylinder "Pacific" type locomotives for the Central Argentine Railway (F.C.C.A) in 1930, with Caprotti valve gear and modern boilers. They were the most powerful locomotives on the F.C.C.A. AW obtained the UK license for Sulzer diesels from 1919, and by the 1930s was building diesel locomotives and railcars. An early example is the Tanfield Railway's 0-4-0 diesel-electric shed pilot, No.2, which was built by AW as works number D22 in 1933. In the same year, the company launched the UK's first mainline diesel locomotive, the 800 bhp "Universal". It