Instrument made up of tubes that contain liquid and a bubble that serve as an indicator, usually held together in a rectangular structure, which is used to measure the straightness of an object or surface.
Point at which a railway track crosses a road, typically with boom gates to regulate traffic.
grade crossingrailroad crossingrailway level crossingtrain crossing
Instrument made up of tubes that contain liquid and a bubble that serve as an indicator, usually held together in a rectangular structure, which is used to measure the straightness of an object or surface.
Point at which a railway track crosses a road, typically with boom gates to regulate traffic.
Instrument made up of tubes that contain liquid and a bubble that serve as an indicator, usually held together in a rectangular structure, which is used to measure the straightness of an object or surface.