PASAR78 These are typically powered by direct current (DC) where the voltage and polarity of the current controls the speed and direction of the DC motor in the train. When both track rails are used for the return in parallel there is much less chance of current interruption due to dirt on the line. American was originally granted the slot as a back-up to Delta's Seattle-Haneda route if it failed to operate on a daily basis on March 28, 2015, (which would give the operating rights to American), but in June 2015, Delta announced the cancellation of its Seattle-Haneda service, claiming the daily operation was not feasible due to the route not being an economically viable one in the Seattle market due to certain regulatory and market conditions. The bi-polar DC carries digital information to indicate the command and the locomotive that is being commanded, even when multiple locomotives are present on the same track.|Value in a Supercar?