The first five locomotives were built by Stephenson between 1820 and 1822, as a development of those at Killingworth - 0-4-0 types with chain-coupled wheels. Four of them had names: Hetton, Dart, Tallyho and Star.
They incorporated his steam springs in an attempt to compensate for the reaction to the vertical cylinders which had caused previous locomotives to rock excessively, and were not entirely successful. For a while a section of the line was operated by stationary engines. The 1822 engine however continued in service until about 1912, being rebuilt in 1857 and 1882, and is now preserved in the National Railway Museum.
The Company acquired limited liability in 1884 and later built two more locomotives, "Lyons" and "Eppleton", 0-4-0T, gear driven, with vertical boilers.