And some of it could be a result of Apple adding more carrier partners in other countries.

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CSX, a struggling Florida-based carrier, is adding 1, 400 new employees to its rail crews.

ECONOMIST: Gridlock on the rails, roads and ports of America

Sprint vice president of network development, Iyad Tarazi, said the carrier has been adding capacity on its LTE service as well as its older 3G network to prepare for the new demands.

WSJ: iPhone Will Stress-Test LTE Networks

The carrier decided to invest in technology rather than adding floor space.

WSJ: Flying Through the Airport

But don't look for Parker to deviate from Southwest's cautious strategy of adding just three cities a year, even if provoked by another carrier's demise.

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The largest wireless carrier in the world saw its profits stagnate in the first quarter of 2013 despite adding more than twice as many subscribers at it used to in previous quarters.

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