It seems like it should be possible. Electric Multiple Units typically have multiple pantographs, drawing power independently for pairs of powered cars in the set. If an electric car / truck piggyback / powered container car required more power than was available from the locomotive, a tender car with a pantograph and transformers could provide that power. The User Fee for the power would be per KWh, so if a train with substantial in-train power consumption ran on the corridor, it would pay higher user fees.