Even with a car's higher rolling resistance, most of the drag at cruising speed ... | Hacker News

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		lutorm 10 months ago \| parent \| context \| favorite \| on: Caltrain's electric fleet more efficient than expe... Even with a car's higher rolling resistance, most of the drag at cruising speed is aerodynamic, though. But a commuter train, by definition, starts and stops a lot so it makes sense that a large fraction of the energy used would be for acceleration.

renhanxue 10 months ago [–]

Aerodynamic drag is proportional to cross sectional area. A train only has maybe 2-3x the drag of a car at the same speed, but it has on the order of 100 to 1000x the mass and momentum. It takes forever for drag to do anything to a train at speed.

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