Automatic lubricator

After condensing, the water sinks to the bottom of the vessel, causing the oil to rise and overflow into delivery pipes.

The behind-smokebox configuration has the advantage that a good connection can be made to the steam pipe and it was used by the Great Western Railway.

It has the disadvantage that the lubricator's accessibility is reduced and additional drain pipes are required to be connected to the waste to avoid it dripping onto the boiler.

[2] Elijah McCoy, a Canadian who moved to Michigan and became a U.S. citizen, received a patent for his automatic lubricator in 1872.

In 1898 McCoy's further patent added a glass tube mounted below the reservoir so that the rate of delivery could be monitored, with a bypass pipe available in case the main feed was seen to be blocked.

Marketed as the Wakefield Lubricator it comprised a large oil chest (typically 1 imperial gallon (4.5 L; 1.2 US gal) for eight delivery tubes) with eccentric-operated pumps submerged within it.

[5][7] The Silvertown lubricator was designed and developed by the Midland Railway in 1911 and from 1922 was commercially available from Gresham and Craven.

This style of mechanical lubricator was used by the London, Midland and Scottish Railway and latter by British Rail, as well as by the various UK private locomotive builders for export overseas.

This style of mechanical lubricator was designed & produced by Alex Friedmann KG of Austria.

[6] Known also as syphon lubrication, equipment using this method consists of reservoirs of oil with delivery pipes from the reservoir to the bearings, axleboxes, slide bars or horn blocks, mounted so that the open top ends of the pipes are above the maximum oil level.

Assemblies called trimmings—bundles of worsted yarn tied around narrow wire frames—are tucked into the open ends of the delivery pipes so that a "tail" of threads drapes into the oil.

The bundles of wool are effective in filtering out harmful contamination but do not work properly should water enter the reservoir.