Locomotive Power Power is defined as “the rate of doing work”. Common units of power in the metric system are Watts (W), kilowatts (kW), Megawatts (MW) and Gigawatts (GW), where 1 Watt = 1 Joule per second = 1 Newton-metre per second. Alternative units of measurement are calories per second and kilo-calories per hour (1 […]
Thermal Efficiency The “thermal efficiency” of any engine is defined as the amount of useful energy output divided by the amount of energy input . It is not a fixed quantum but varies according to the engine’s load and conditions of operation. In the case of steam locomotives, the term thermal efficiency may refer to […]
Should not the 5AT be a more radical design incorporating more innvotive features? In Feb 2009, the following question was asked by a reader in Minnesota, USA: “Why, when you are from the country that rbulleally brought innovation to steam design still persist thinking inside the box? Bulleid went outside the box with the Leader […]
There are six interrelated properties that define the state of steam: Temperature Pressure Dryness Fraction (within the saturated zone) Enthalpy Internal energy Entropy Fixing the value of any two properties defines the value of all the others. Thus fixing the values of Enthalpy and Entropy is sufficient to define Temperature, Pressure and Internal Energy of […]
Steam Tables Steam tables used to be (and may still be) published in the form of a small booklet listing values of steam temperature, pressure, specific volume (i.e. the volume of 1kg of steam at a given temperature and pressure), specific entropy, specific enthalpy against various input values, separate sets of tables being provided for […]
Anomalies in Thermodynamics Draft Text Only – Readers’ suggestions and inputs are welcome Thermodynamics is not an easy subject to master and there are many instances where it defies intuitive judgement. The following examples are offered by way of enlightenment and perhaps education: Steam viscosity increases with temperature Whilst it is intuitive that liquids become […]
Enthalpy is a “term of convenience” that is useful in the interpretation and application of Thermodynamics. Enthalpy is basically a measure of energy, but its main function is in the calculation and measurement of “flow energy” or gaseous energy (e.g. steam energy). [Note (borrowed from mathpages.com): Enthalpy is not a specific form of energy. It […]
Entropy Draft Text Only – Readers’ suggestions and inputs are welcome When a car or locomotive runs or brakes, we say that the heat escaping from it is “lost”. The Second Law of Thermodynamics explains this by saying that “energy will tend to dissipate from a hot or high energy body to a cold or […]
Page Under Development This page is still “under development”. Please contact the webmaster@advanced-steam.org if you would like to help by contributing text to this or any other page. Thermodynamics Nomenclature: T = temperature (oK) V = volume of system (cubic metres) P or p = pressure at the boundary of the system and its environment, […]
Draft Text Only – Readers’ suggestions and inputs are welcome Introduction Oliver Bullied, disciple of Gresley and famously progressive CME of the Southern Railway, is often quoted as saying “Thermodynamics never sold a single locomotive” (or words to that effect) when commenting on Chapelon’s contemporary locomotive developments in France. Whether true or apocryphal, the remark […]
Page Under Development This page is still “under development”. Please contact the webmaster@advanced-steam.org if you would like to help by contributing text to this or any other page. Definitions of thermodynamic concepts such as Entropy and Enthalpy are provided on separate pages of this website. Numerous useful (and often diverse) definitions of these and other […]
The following answer is taken from Wardale’s response to a letter from Angus Eickhoff, published in Steam Railway #276 (see ‘Articles and Letters’ page of this website): “Compound expansion for the 5AT has been considered – and rejected. The arguments for and against compounding are too complex to air here, but I am firmly convinced […]