现存的联邦铁路局轨道安全标准十分全面，对高达200英里/小时（约合322公里/小时）的速度指定了FRA 1～9类这9种类型的轨道几何形状和欠高。

Existing FRA tracksafety standards are comprehensive and specify track geometry and cant deficiency for FRA Classes 1 through 9 at speeds up to 200 mph.

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主要技术要求是刀具的几何形状的正确性和加工工艺过程可靠性，文中主要介绍两种较易实施且安全可靠的加工方法。

The essential techniques is the validity of the tools shape and reliability of craft here, this paper tells two easy and sale & reliable methods to process.

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