New Age Railroading

Two Evolution-Series locomotives with Oakland-bound shipping containers stand at the Davis, California, signal tower. They await a morning commuter train to clear the track. The light turns green to depart.
These modern locomotives, dubbed "world's cleanest locomotives" were designed with six years and $200 million of research and development by the modern railroad industry. At up to 4400 horsepower, these locomotives have no compromises at the draw bar while lowering emissions and increasing fuel efficiency.
A gasp of air hisses through the snaking brake line as the engineer does a safety inspection and the sea container platforms prepare to roll. The lead locomotive blasts two bursts of horn. "Highball" is signaled.
A small whiff of exhaust hits my senses as the locomotives grind past. Clunk, Clunk, Clunk, Clunk, a flat wheel approaches and rolls along in pain. This car will be made note of, and the defect will be quickly swapped out on the modern railroad.
This is new age railroading. Many sea containers cross the United States from the Atlantic to the Pacific as a land bridge in order to avoid Panama Canal congestion. Domestic containers belonging to the railroads and trucking companies are quickly pulled off of the train at the destination and are routed for distribution. Modern trains allow truck trailers to be removed from their chassis to become stacked two high, helping satisfy the world's need for fuel-efficient transportation.
The locomotives throttle up; 30 miles per hour, 50 miles per hour. The cars whine with precision over the steel rail. The train has momentum. This is new age railroading. America is in motion.

Sources:

http://www.dieselnet.com/standards/us/loco.php
http://findarticles.com/p/articles/mi_m0BQQ/is_11_43/ai_110728325

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