| Résumé | In the search for increased efficiency the railroads have been changing operations towards the use of longer trains. Longer trains require less crew per ton of freight transported, reduce the number of train slots taking up a position on the infrastructure, reduce scheduling conflicts (“train meets” on line), and reduce the number of times that crossings are blocked by trains. Fuel consumption is improved with longer trains though reduced wind resistance per car and through reduced idling times when one train must stop to let another pass. Long trains are seeing expanded use across Canada, especially along the country's busiest traffic corridors. But while the advantages of long trains are considerable, they are not without added cost and risk. Longer, heavier trains require more locomotive power which, for conventional trains with head-end power, increases the draft and buff loading required to accelerate and decelerate the train. As well, as trains negotiate curves and grades, slack in the couplers causes longitudinal train action to arise, resulting in significant forces between cars as the train stretches and compresses. Large in-train forces damage track and cars, couplers and lading, and in severe cases large in-train forces can be a primary or secondary contributor to derailments. |
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