if we were to design a locomotive for a specific application.How would operation environmental influence the design
bob Amara if we were to design a locomotive for a specific application.How would operation environmental influence the design
How limited is the application - and how small is the market for the application?
You don't make anything for a market that is not large enough to support what you are making.
Never too old to have a happy childhood!
As an example, consider the export market. Locomotives often have to be designed with lighter axle loadings for less substantial track and with smaller carbodies to fit in tighter clearances.
at least in the steam era, I had read that the Philadelphia and Reading railroad designed locomotives for a specific routes and purpose (e.g. 100 car coal trains from the coal region to Philadelphia). Of course such a locomotive could be used elsewhere.
I believe the same is true for airliners today. Boeing and Airbus have specific type of routes (distances) and loads that they design the aircraft for to minimize cost. This is certainly true for military cargo and fighter aircraft where performance is critical.
I don't believe it's a question of capability, but operating cost.
greg - Philadelphia & Reading / Reading
ndbprrI would think that the engines for Saudi Arabia and possibly Australia would have increased air filtration due to sand Issues
In general, there aren't sandy deserts in Australia and filtration isn't required to the same extent as Saudi Arabia.
Heat is a problem, however. The ES44DCi and ES44ACi units are built on the longer frame (around three feet longer) used for the AC 6000 and have the AC6000 radiator and two cooling fans instead of one. Strangely, this only applies to the GE units. The EMD SD70 ACe units used in the same area have standard radiators. This must make the EMD units much more competitive in price compared to GE for use in the Pilbara area of Western Australia.
I assume from this that the GE is much more sensitive to high temperatures. Since there are no requirements to meet specific emissions requirements in Australia, I assume the bigger radiators are needed to meet the fuel consumption requirements in this case.
The Dash 9-44CW units had standard radiators but larger cooling air openings to assist with keeping the airflow up. Even the openings for rear number boards were left open as air ducts.
But ambient temperature is an important consideration in locomotive design.
M636C
gregc at least in the steam era, I had read that the Philadelphia and Reading railroad designed locomotives for a specific routes and purpose (e.g. 100 car coal trains from the coal region to Philadelphia). Of course such a locomotive could be used elsewhere. I believe the same is true for airliners today. Boeing and Airbus have specific type of routes (distances) and loads that they design the aircraft for to minimize cost. This is certainly true for military cargo and fighter aircraft where performance is critical. I don't believe it's a question of capability, but operating cost.
During the steam era in North America locomotives were usually custom designed by the railroad ordering them for specific territories and operations. One great impetus towards dieselization was the fact that diesel locomotives were in many cases much more versatile and the manufacturers pushed standardization.
This trend toward standardization has accelerated over the years leading to fewer different models being offered by EMD and GE.
Off topic but what Boeing and Airbus offer the market are variations on a relatively small number of basic aircraft designs or families for specific markets.
The trend with military aircraft is also towards more versatility and if you compare the number of different aircraft types operated by the USAF and USN 50 years ago versus today you can see that..
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Have a look at the Saudi SD70ACe's, the air intakes have a method of cleaning themselves of sand.
bob Amaraif we were to design a locomotive for a specific application, how would operational environment influence the design?
To add to what M636C noted, consider the 'tunnel motors'. Operation in snowsheds made high-mounted air intakes for the radiators undesirable. So taking in cooler air through large intakes mounted down low is an advantage.
Don Oltmann made a point in a different recent thread about how radial-steering trucks allow SD80MACs to go places that considerably lower-horsepower locomotives (like conventional SD40-2s) have trouble negotiating.
Baldwin was making locomotives for Saharan sand conditions as early as the '40s. Will Davis cwn probably provide a better detail reference than I can.
In a different connection, look at how UP used their 'double diesels' effectively -- and how changes in operating patterns led to the demise of those locomotives later. I think I would associate the periodically-recurring desire for cabless locomotives with this; you need an operation that benefits from comparatively large consists that don't change 'leaders' that often (and that pinches the pennies enough to adapt operating policies to accomplish that as a goal, perhaps). On the other hand, remember those BQ23-7s that had their cabs plated over to allow them to keep running?
Dieselization drastically reduced the need for special purpose designs in North America. Multiple-unit control, allowing one, two, or as many as five units to be operated as one locomotive allows one type to serve many uses. The road-switcher concept, same simplification. A given design can be ordered with different gear ratios. Optional head-end power for passenger service.
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