tóng​guǐ

same gauge

同轨 同軌 tóng​guǐ
same gauge
(bound form) refers to vehicles having the same axle width or railroads having the same track gauge; often refers to standardizing measurements and systems
unified
(literary) unified or standardized; having one law or culture throughout the country; often used in the phrase 书同文 shū​tóng​wén, 车同轨 chē​tóng​guǐ meaning standardized writing and standard axle widths
identical methods
(literary) using the same methods, rules, or standards; following the same path or principle
to travel together
(literary) to travel along the same road or in the same carriage
states with shared rites
(literary) vassal states or domains that share the same system of rites and music