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[quote user="MichaelSol"][quote user="Bucyrus"] But still, both locomotives exhibit a similar rate of TE fall-off as speed increases.  The only difference is that the diesel TE falls off faster and is higher in the beginning.  As you point out, the diesel's high TE at the beginning is not useful, but is it really a penalty?  It seems to me that it is a consequence of the electric transmission that may or may not be useful, but is not a penalty assuming that the transmission is a necessary attribute for overall performance.[/quote]It costs money. In the example where the company wants to run the train at 30 mph, it needs five of the Diesel-electric version to equal or exceed the tractive effort available from two of the Steam engines. That requires the 300,000 lbs of TE of mostly reserve and useless TE capacity at 5 mph, compared to the 118,000 lbs of TE available to the Steam power; both of which are in place for a train that requires just under 15,000 lbs TE at 5 mph.At 1955 prices, that is the difference between a $320,000 investment or a $1.7 million investment. That's a $1.4 million penalty paid to have a huge excess of TE at low speeds that is useless compared to the actual needs of the train at low speeds, but which is necessary to have the TE in order to operate the train at the higher speed that the Steam engines can run that train. But, its a $1.4 million penalty at 30 mph as well because that is what is necessary to spend to purchase the equivalent Diesel-electric TE necessary to move the train at 30 mph.It is the need to purchase a huge reserve of TE at low speeds, in order to have enough TE at higher speeds, that represents a financial investment penalty because the unused TE still costs money.[/quote]I asked if the diesel's production of excess TE at the lowest speed was really a penalty.  You answered that TE costs money, so it is wasted money if it is produced at a speed where it is not needed.  I understand that explanation, however, it raises another question that is the basis of my first question.  Is the cost of TE the same no mater what speed it is produced at, or does the cost per pound of TE rise as the speed rises?It seems to me that the high TE produced by diesel locomotives at starting speeds is the result of being able to "gear down" its prime mover while it operates at full throttle, and if the steamer were similarly equipped with a transmission to enable it to start in "low gear," at high throttle, it too would exhibit high starting TE.  And yet, if you took away its transmission gearing, the extra low speed TE lost could not be utilized at higher speeds.  And the same would be true of the diesel, although its transmission is a fundamental component.  So that is why I asked if the high TE possessed by the diesel at starting is really a penalty, or at the expense of the TE it needs at higher speeds.
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