For the rapidity and traffic density of trains on high-speed railway, larger traction power is needed, so the electric power supply is adopted.

高速铁路列车速度快、行车密度大，要求牵引功率高，电力牵引成为高速铁路动力牵引的必然选择。

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The paper hence suggested that to achieve transportation task for year 2000, China rail way should actively increase in train density while raising traction load of trains.

提出为完成2000年的运输任务，今后在大力增加列车牵引重量的同时，还应积极加大列车密度。

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Based on this guidance, the CDC preparedness plan devotes dozens of pages to potential NPIs, from voluntary isolation to reorganizing company work schedules to reduce the density of people sitting next to each other in the office or while riding trains and buses.

CNN: Scientists dig for lessons from past pandemics