Of the two beam engines, that make up the Crofton Beam Engines, the older one, an original Boulton & Watt from 1812, can claim the very precise title of the "Oldest working beam engine in the world still in its original engine house and capable of doing the job for which it was installed."
Indeed for a short period in 2007 it was pressed into service to do that job, when the replacement electric pumps failed.
The bit about being in its original engine house is important, as you quickly realise if you visit on a steaming day. The building is an integral part of the machine; it is the frame that holds the various components together. The whole building shudders as the beams rock up and down, and you realise that you are actually walking around inside the machine.
Taking an old beam engine out of its house effectively removes a major part of the original structure of the machine.
Installed alongside the Boulton & Watt machine is a younger machine by Harvey & Co. of Hayle in Cornwall. This dates in part from 1843, but was significantly modified in 1908. It replaced an even earlier Boulton & Watt engine which was second-hand when it arrived at Crofton in 1809.
The original waggon boilers were replaced by Cornish boilers in 1843. These were in turn replaced by two hand-stoked, coal-fired Lancashire boilers in around 1905. The faceplate of one these boilers is still in place, the rest having been removed to make way for the tea rooms.
The other boiler was condemned in 1986, and was replaced with one from the Imperial Tobacco Co. in Bristol.
The engines were retired in 1959 after the top of the chimney (which dates from 1856) had to be removed due to deterioration.
Due to the efforts of the former Resident Engineer, Frank Wilmot, the pumps were kept in good condition until the Kennet & Avon Canal Trust could take over the site in 1968, and begin the process of restoration. The engine house was formally reopened by Sir John Betjeman in August 1970, the 1812 engine having successfully run the previous month. The top of the chimney was eventually rebuilt in 1997.
For opening times, steaming dates, admission prices, etc. please see the Crofton Beam Engines official site, detailed below.
All together now, "The steam is on the beam, The point is that the joint is jumpin'". Oh! Only me then.