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Why so few SD.80 MACS?
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There's been a significant increase in fuel efficiency in the last 50 years: <br />Fuel consumption at notch 8: <br /> <br />SD9: 108 gal/hr, or 16.2 hp/gal/hr <br />SD40-2: 164 gal/hr, or 18.2 hp/gal/hr <br />SD70MAC: 192 gal/hr, or 20.8 hp/gal/hr <br /> <br />In other words, for one gallon of fuel, the SD70MAC does 28% more work than the SD9. <br /> <br />Imagine that over the 15-year lifetime of a locomotive, it works in notch 8 two hours a day and is shut off the rest of the time -- a simple approximation of what it does. The fuel burned and work performed is: <br /> <br />SD9: 1,182,870 gal for 19,162,500 hp-hours <br />SD40-2: 1,804,945 gal for 32,850,000 hp-hours <br />SD70MAC: 2,105,769 gal for 43,800,000 hp-hours <br /> <br />We can get the SD9 and SD40-2 to perform the same amount of work by working them a few extra minutes every day, but there's a fuel penalty. Assume that diesel fuel for the 15 year period is $1/gal: <br /> <br />For the SD9 to generate 43,800,000 hp-hours it will burn 2,703,703 gal <br />For the SD40-2 to generate 43,800,000 hp-hours it will burn 2,406,593 gal <br />SD9 extra fuel burn 597,934 gal, extra cost $597,934 <br />SD40-2 extra fuel burn 300,824 gal, extra cost $300,824 <br /> <br />If you run your locomotives 30 years, which is not unreasonable, the fuel savings of the SD70MAC over the SD40-2 pays about half of the SD70MACs initial cost. <br /> <br />Consider maintenance -- either the SD9 and SD40-2 has to work more hours to do the same work, or you need more SD9s and SD40-2s. If parts cost the same and wear out at the same rate, the SD9 will cost you 28% more, and the SD40-2 14% more. <br /> <br />I hadn't run these numbers before, and admittedly they're crude approximations, but I'm beginning to understand why, even though an SD40-2 is still a good locomotive, UP has acquired over 1000 SD70Ms. <br /> <br /> <br /> <br />
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