Subway rail construction lower layer assembly trolley

The utility model discloses a lower layer assembly trolley for subway track construction in the technical field of tunnel construction, which comprises a frame and a guardrail component positioned on the frame, the frame comprises a left main frame and a right main frame which are symmetrically arranged, and each main frame comprises four upright posts, and a lower cross beam and an upper cross beam which are arranged between the upright posts; an inner lower triangular support and an inner upper triangular support are arranged on the inner side of the main frame, an auxiliary platform is arranged on the outer side of the main frame, the plane of the outer upper triangular support and the plane of the inner lower triangular support are flush with the plane where the lower cross beam is located, and the plane of the inner upper triangular support and the plane of the outer upper triangular support are both flush with the plane where the upper cross beam is located. A lower-layer connecting belt and an upper-la