| Power Classification | |
| Introduced | c1814 |
| Designer | William Hedley |
| Company | Wylam Colliery |
| Weight | 8t 5cwt |
| Driving Wheels | 3ft 3ins |
| Boiler Pressure | 50psi |
| Cylinders | 9in x 36in |
| Tractive Effort | |
| Valve Gear |
Puffing Billy is the oldest surviving steam locomotive.
Puffing Billy was one of the three similar engines built by engineer William Hedley, enginewright Jonathan Forster and blacksmith Timothy Hackworth, the resident engineer at Wylam Colliery, to replace the horses used as motive power on the tramway.
Definitive records regarding the construction of Puffing Billy do not exist. The exact construction dates are not known for certain, although it was known to be in operation during 1814.
It was the first commercial adhesion steam locomotive, employed to haul coal chaldron* wagons from the mine at Wylam to the docks at Lemington-upon-Tyne in Northumberland.
*The chaldron was the legal limit for horse-drawn coal wagons travelling by road as it was considered that heavier loads would cause too much damage to the roadways. The chaldron was used as the measure for coal from the 13th century, measuring by volume being much more practical than weighing low-value, high-bulk commodities like coal. It was not standardized, and there were many different regional chaldrons, the two most important being the Newcastle and London chaldrons. The Newcastle chaldron was used to measure all coal shipped from Northumberland and Durham, and the London chaldron became the standard measure for coal in the east and south of England.
Puffing Billy had a number of serious technical limitations. Running on cast iron Wagonway plates, its eight-ton weight was too heavy and broke them, encouraging opponents of locomotive traction to criticise the innovation. This problem was alleviated in 1815 by redesigning the engine with four axles so that the weight was spread more evenly.
The engine was eventually rebuilt as a four-wheeler when improved edge rails track was introduced around 1830. It was not particularly fast, being capable of no more than 5 mph.
Puffing Billy incorporated a number of novel features, patented by Hedley, which were to prove important to the development of locomotives. It had two vertical cylinders on either side of the boiler, and partly enclosed by it, and drove a single crankshaft beneath the frames, from which gears drove and also coupled the wheels allowing better traction.
Puffing Billy remained in service until 1862, Edward Blackett, the owner of Wylam Colliery, lent it to the Patent Office Museum (now the Science Museum) in South Kensington, London (later the Science Museum). He later sold it to the museum for £200. It is still on display there.
A replica has been built by Alan Keef Ltd and first ran in 2006 at Beamish Museum. Another replica, built 1906 in a Royal Bavarian State Railways workshop, can be found in the German Museum, Munich.
Puffing Billy was an important influence on George Stephenson, who lived locally, and its success was a key factor in promoting the use of steam locomotives by other collieries in north-eastern England.
It also entered the language as a metaphor for an energetic traveller, and phrases like “puffing like Billy-o” and “running like Billy-o” are thought to derive from the locomotive’s name.
| Home Base | Current Status | Owner |
| National Railway Museum – York | On static display | National Railway Museum NRM Object Number{1862-2} |
There is also a working replica of Puffing Billy at Beamish Museum which was built there in 2005.
Preserved British Steam Locomotives 