No steam locomotive
ever built included all the available proven techniques to maximize its performance
in service.
This fact, more than any other factor, is what lead to the downfall of world
steam.
On this page I try to give a brief overview of the developments since 1930. These developments continue until today in a small but devoted community.
In the era from 1930-1950 Chapelon has proved in France on large scale that raising a steam locomotive's efficiency by as much as 30% was feasible. Remarkably he never designed a new French locomotive but he always proved his ideas by rebuilding existing designs.
His most important points (but certainly not all):
Better gas flow
Flowing gas undergoes friction from the tube sides. Use of wide steam tubes
and avoiding sharp bends, thus allowing free flowing of the hot gases ,lessened
the flow resistance dramatically
Higher pressure in the cylinders
To his horror Chapelon noted that engineers had the habit of throttling down
the steam pressure to control the locomotive. Driving with low pressure and
large cut-off is for various reasons far less efficient than driving with
high pressure and low cut-off. Retraining engineers had tremendous effect
on efficiency.
Less condensation
Condensation of steam in the cylinders causes loss of power. By introducing
steam channels in the block that were flushed with used steam condensation
was reduced to a minimum.
Multiple expansion
By consistently using double (or even triple) expansion and mathematically
optimizing the multiple expansion system he achieved amazing results. He proved
that multiple expansion, as opposed to general belief, was quite suitable
for superheated steam locomotives.
Less counter pressure in the exhaust system
To raise draft on the fire used steam from the cylinders was used to
create a "vacuum" in the smokebox and to eject the hot gases through
the stack. The operation of this used steam jet in the exhaust system caused
back pressure in the cylinders thus causing loss of power. Chapelon designed
an exhaust system (Kylchap
ejector) that had minimum back pressure and left more power for the engine.
One of the disadvantages of Chapelon's work is that it often necessitates radical reconstruction (almost to down right rebuilding) of the locomotive to achieve the desired results.
This apprentice of Chapelon took development steps further. His work, contrary to Chapelon's, is tuned toward more readily applicable improvements rather than complete rebuilding, because he already lived in a time were such rebuildings were not easily undertaken anymore.
Further optimization of the exhaust system
By developing the Lempor exhaust
he was able to take Chapelon's calculations and results one step further.
To date the Lempor exhaust system is probably the most efficient exhaust system
so far.
This all leads to less boiler wash outs, less off time, less maintenance, less repairs and eventually to longer lifetime of boiler and machine.
Gas Producer Combustion System
The GPCS is a series of measures
in the firebox to improve firing in solid fuel boilers. Air is not sucked
through the fire bed but is mainly led from air ducts over
the fire causing turbulence and mixing air and fire gases thoroughly. A GPCS
leads to
Both Chapelon and Porta have founded their improvements on methodical reasoning and mathematical calculations.
Roller bearings
Roller bearings have gradually taken their place in steam locomotive building
since the mid 40's. They offer
Electric preheating
The classical steam locomotive had to be lit hours in advance. Steam had
to raised carefully and slowly to minimize stresses in the firebox and boiler.
The modern steam locomotive can be heated by an external electrical heating
device resulting in
Oil firing
Oil firing is known and used since the 50's. Current technology enables
a better and more efficient burning of liquid fuels.
Advantages
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