案例库 · 工程与运营 · 运营决策 · 1960–1978
这条还没译成中文，下面是英文原文。
Southern Railway's 1960 unit train shuttled one commodity, so each car worked far harder.
Southern Railway dedicated an entire train to one commodity shuttling between mine and plant, cutting cost per ton by using its cars far harder.
Southern Railway
那一手
A railroad freight car spends much of its life sitting, waiting to be switched, loaded or routed through a yard. The more it sits, the more each haul has to pay for the idle hours.
Southern Railway originated the unit train when it went after coal-for-utilities business. A unit train is wholly dedicated to one commodity between fixed points, running back and forth without being broken up.
Because the cars are loaded nearly continuously, a 100-car coal train worth about $4.66 million lifts the same volume as a general-service fleet costing about $22.1 million, with equipment working six to eight times harder. The first one ran in 1960 between Alabama mines near Parrish and SEGCO's plant at Yellowleaf.
The idea spread, and Southern built the Appalachia Transloader in 1966 to gather, wash and blend coal from many small mines into unit trains, by which time about half of Southern's utility coal moved by unit train and coal was 27.8% of its 1978 tonnage.
为什么管用
- A dedicated train is not switched or yarded, so it spends time hauling
- Continuously loaded cars do the work of far more idle cars
- One commodity and one route remove the sorting that eats turnaround time
可以搬走什么
Specialization beats flexibility when a flow is steady: reserving the whole asset to one route and product turns that asset from idle much of the time to earning most of the time.
后来呢
The unit train became the industry standard for bulk commodities like coal and grain, and was the railroads' answer to the coal slurry pipeline and to cheaper barge and truck competition.
资料来源
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