Robert Stephenson and Co: Invicta
The first engine of this name was built in 1825.
This may be described as a coupled engine of the "Rocket" type, but the steeply inclined cylinders, which were 10.8in. by 18in., and bolted to two iron frames, were placed at the front end of the boiler instead of at the fire-box end, as in the Rocket. As originally built, the Invicta had a fire-box outside and at the back of the boiler barrel, and the boiler was of the multitubular type, similar to that of the Rocket. It carried 40 lb. pressure. The coupled wheels had a diameter of 4ft. The wheel base on the original drawing was 4ft. 7in., but when the alterations mentioned below were made, the wheel base was lengthened to 6ft. About 1838 the fire-box and tubes were removed and a cylindrical furnace within the boiler was substituted. From this furnace three tubes extended forward to a makeshift smoke-box underneath the chimney. It was stated that after this alteration there was difficulty in maintaining steam. Whishaw stated that in 1839 the use of the locomotive had been discontinued, but it is still preserved.
Sources of Information
- The Engineer 1925/01/09
- The Engineer 1875/10/01