Northumbrian was an early steam locomotive

Steam locomotive

A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...

 built by Robert Stephenson

Robert Stephenson

Robert Stephenson FRS was an English civil engineer. He was the only son of George Stephenson, the famed locomotive builder and railway engineer; many of the achievements popularly credited to his father were actually the joint efforts of father and son.-Early life :He was born on the 16th of...

 in 1830 and used at the opening of the Liverpool and Manchester Railway

Liverpool and Manchester Railway

The Liverpool and Manchester Railway was the world's first inter-city passenger railway in which all the trains were timetabled and were hauled for most of the distance solely by steam locomotives. The line opened on 15 September 1830 and ran between the cities of Liverpool and Manchester in North...

. It was the last of Stephenson's 0-2-2

0-2-2

An 0-2-2, in the Whyte notation for the classification of steam locomotives by wheel arrangement, is one that has two coupled driving wheels followed by two trailing wheels, with no leading wheels...

 locomotives in the style of Rocket

Stephenson's Rocket

Stephenson's Rocket was an early steam locomotive of 0-2-2 wheel arrangement, built in Newcastle Upon Tyne at the Forth Street Works of Robert Stephenson and Company in 1829.- Design innovations :...

, but it introduced several innovations. It was the first locomotive to have the Stephenson type firebox incorporated in the boiler, and having a smokebox

Smokebox

A smokebox is one of the major basic parts of a Steam locomotive exhaust system. Smoke and hot gases pass from the firebox through tubes where they pass heat to the surrounding water in the boiler. The smoke then enters the smokebox, and is exhausted to the atmosphere through the chimney .To assist...

 the full diameter of the boiler, it therefore had the first true 'locomotive' boiler. It also had plate frames, a proper tender, and the cylinders set at a relatively low angle to the horizontal, giving smoother running. The pace of development of locomotive design at the time can be seen by comparing this engine with Stephenson's Planet

Planet (locomotive)

Planet was an early steam locomotive built in 1830 by Robert Stephenson and Company for the Liverpool and Manchester Railway. The ninth locomotive built for the L&MR, it was Stephenson's next major design change after the Rocket. It was the first locomotive to employ inside cylinders, and...

, produced later the same year.