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[quote user="MichaelSol"] The "power characteristics" are considerably different. As a given train tonnage attempts to increase in speed, the Davis Formula shows that increasing horsepower is required to keep moving the train. The Diesel-electric puts out a pretty good hp at low speeds -- where it isn't required. It "craps out" at the higher speeds because its ability to continue to develop horsepower is remarkably limited. The reciprocating steam engine continues to develop horsepower at higher speeds -- exactly where the train needs higher horsepower! For locomotives with comparable weight on the drivers, a given set of train and tonnage conditions, they would compare as follows:<table border="0" cellspacing="0" cellpadding="0" width="349" style="width: 349px; height: 288px"><tbody><tr height="17"><td width="64" height="17">MPH      </td><td width="91">Diesel-electric         </td><td width="64">Steam </td><td width="82">      HP  needed</td></tr><tr height="17"><td height="17">5</td><td>    4,278</td><td>1,806</td><td>         307</td></tr><tr height="17"><td height="17">10</td><td>    5,133</td><td>3,613</td><td>         743</td></tr><tr height="17"><td height="17">15</td><td>    5,600</td><td>4,516</td><td>      1,239</td></tr><tr height="17"><td height="17">20</td><td>    5,600</td><td>5,600</td><td>      1,839</td></tr><tr height="17"><td height="17">25</td><td>    5,600</td><td>6,323</td><td>      2,562</td></tr><tr height="17"><td height="17">30</td><td>    5,600</td><td>7,226</td><td>      3,426</td></tr><tr height="17"><td height="17">35</td><td>    5,600</td><td>7,677</td><td>      4,446</td></tr><tr height="17"><td height="17">40</td><td>    5,600</td><td>7,948</td><td>      5,641</td></tr><tr height="17"><td height="17">45</td><td>    5,600</td><td>8,129</td><td>      7,028</td></tr><tr height="17"><td height="17">50</td><td>    5,600</td><td>8,310</td><td>      8,624</td></tr><tr height="17"><td height="17">55</td><td>    5,600</td><td>8,400</td><td>     10,447</td></tr><tr height="17"><td height="17">60</td><td>    5,600</td><td>8,310</td><td>     12,513</td></tr><tr height="17"><td height="17">65</td><td>    5,600</td><td>8,219</td><td>     14,840</td></tr><tr height="17"><td height="17">70</td><td>    5,600</td><td>8,129</td><td>     17,445</td></tr></tbody></table>As this shows, the Steam engine doesn't put out nearly the hp at 5 mph, but it also doesn't need much. It has plenty of power to move the train. Above 20 mph the Steam engine has more hp available for acceleration than the Diesel-electric. At about 40 mph, the Diesel-electric poops out, and doesn't have enough power to continue to move the train, but the Steam engine continues to develop the horsepower necessary to keep the train moving and continues to do so to nearly 50 mph. At 70 mph, two Steam engines are able to provide the work that requires three Diesel-electrics. It does this at approximately 40% of the capital cost of the Diesel-electric, and, now, at approximately 20% of the operating cost. [/quote]Thanks for posting this information.  In looking over this table, I have some comments and questions.  I don't know that I would interpret this as showing the diesel crapping out at higher speeds, or rather, a confirmation that the diesel can deliver nearly its full horsepower at very low speeds whereas steamers cannot.  Actually I do not understand why the diesel cannot deliver its 5600 hp at 10 and 5 mph as well as all other speeds.  I am guessing that the answer to that question might be a limitation in traction motors.Also, it appears to me that the comparison is between a 5600 hp diesel locomotive and an 8400 hp (or higher) steam locomotive, which furthers the suggestion that the diesel stalls out on producing more horsepower needed for higher speeds. I do not understand why the horsepower of the steamer falls off as its train speed increases from 55 to 70 mph.  I thought that any time the speed is increased, more horsepower is required to do so.  What does the last column of figures on the right indicate?
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