Riding under ground的意思

"Riding under ground" is an English phrase that typically refers to the act of traveling by train or other transportation means through a tunnel beneath the surface of the earth. This phrase is often used in the context of urban transportation systems, such as the London Underground or the New York City Subway, where passengers ride on trains that run through tunnels beneath the city streets.

The phrase can also refer to other types of underground transportation, such as mining trains or people movers in underground facilities. In some cases, "riding under ground" may also be used metaphorically to describe any situation where someone is traveling or moving through an underground or hidden pathway or system.