A gantry is a high metal structure that supports a set of road signs, railway signals, or other equipment.
例句
On top of the gantry the American flag flew.台架顶上飞舞着美国国旗。...the lighting gantries.照明塔架
英英词典释义
Noun
1. a framework of steel bars raised on side supports to bridge over or around something; can display railway signals above several tracks or can support a traveling crane etc.