A theoretical minimum amount of oxygen is needed to react with the combustible elements (mainly carbon and hydrogen) in a given quantity and type of fuel. In practice an additional (or excess) quantity of air is required to ensure adequate contact between fuel and oxygen to guarantee efficient combustion. There are no hard-and-fast rules defining […]
Lack of steam tightness is usually imagined to be associated with steam leaking from pipe joints and piston rod glands resulting in the familiar leaks that can be seen as a white plume of steam eminating from wherever the leak is occurring. Steam leakage of this sort is indeed wasteful and deletarious to a locomotive’s […]
Locomotive and Train Brakes There are three types of brakes used in railway operations: the Air Brake, the Steam Brake and the Vacuum Brake. Steam Brake (steam locomotives only): steam brakes are used only on steam locomotives and their tenders. Steam brakes use the steam from the locomotive’s boiler to generate the braking force that […]
Locomotive Exhausts Page Under Development This page is still “under development”. Please contact Chris Newman at webmaster@advanced-steam.org if you would like to help by contributing text to this or any other page.’ Background A steam locomotive’s exhaust system is perhaps the most innovative of all the ideas that underpin the “Stephensonian” concept. It’s cleverness derives […]
Incomplete Expansion of Steam in the Cylinder Page Under Development This page is still “under development”. Please contact Chris Newman at webmaster@advanced-steam.org if you would like to help by contributing text to this or any other page. The term “incomplete expansion” is used to describe the curtailment of the expansion of steam inside a locomotive’s […]
How to construct a Reuleaux Diagram Whilst the exact movements of a locomotive’s valves are indeterminate because of the angularity effects of both connecting rods and eccentric rods, a close approximation of its valve events can be found through constructing a Reuleaux diagram in which the angularities are ignored. Porta used these as a first […]
Cylinder Clearance Volume The clearance volume of a cylinder (often presented as a percentage term) is that part or proportion of the cylinder volume that is not swept by the piston. It is therefore the volume (or proportion of total volume) taken up by the steam passages and cylinder-head cavities – i.e. the volume contained […]
Steam Chest The steam chest (or steamchest) is the “reservoir” for collection of steam as it passes between the superheater header and the inlet port to the cylinder. The advantage of a large steam chest (as is the advantage of any reservoir) is that fluctions in pressure as the steam passes from the steamchest into […]
Superheating of Steam Page Under Development This page is still “under development”. Please contact Chris Newman at webmaster@advanced-steam.org if you would like to help by contributing text to this or any other page.’ Background On page 160 of his book “The Red Devil and Other Tales from the Age of Steam” Wardale confirms that: “The […]
Primary and Secondary Combustion Air and Combustion Gases Combustion Air is the air drawn through the firebox by the draughting system which allows combustion to take place. Only the oxygen content of the air (approx 18%) is used in the combustion process, the remainder (mostly nitrogen) being inert and serving no function other than wasting […]
Dynamic Augment or Hammer Blow Hammer Blow or “Dynamic Augment” is a dynamic force imposed through the driving wheels and onto the railway track resulting from the rotation of out-of-balance weights that are attached to the driving wheels for the purpose of counteracting the horizontal inertia forces resulting from the “to-and-fro” motion of the reciprocating […]
Snifting, Drifting, Bypass and Herdner Valves Snifting, Bypass and Drifting Valves were commonly used as a means of preventing negative pressures occurring in the cylinders of a locomotive during “drifting” or free-wheeling. If a negative pressure does occur, it will immediately result in combustion gases and solid particulates being sucked down from the smokebox through […]