A swing hinge and gate assembly comprising: a. a gravity-closing gate, wherein a portion of the gravity-closing gate comprises a hinge pin hole disposed therethrough; b. a swing hinge assembly configured to be selectively attached to a guardrail on a first side of a guardrail opening or a second side of the guardrail opening, to allow the gravity-closing gate to open in either direction by rising from a lowest neutral position, wherein the swing hinge assembly comprises: (i) an upper hinge portion comprising a hinge pin thru hole; (ii) a back portion connected between the upper hinge portion and a lower hinge portion, wherein the lower hinge portion comprises a hole formed therein, and wherein the hole is axially aligned with the hinge pin thru hole along a hinge axis; and (iii) a recess formed in the swing hinge assembly between the upper hinge portion and the lower hinge portion, wherein the recess comprises an angled hinge face of the lower hinge portion, sloping upwards into the recess in one or more directions, and wherein the recess opens outward from the back portion and receives the portion of the gravity-closing gate having the hinge pin hole; c. a hinge pin disposed through the hinge pin thru hole, through the hinge pin hole, and at least partially into the hole, thereby attaching the gravity-closing gate to the swing hinge assembly; and d. wherein the angled hinge face is oriented upward, whereby the gravity-closing gate rises in either direction away from the lowest neutral position on the angled hinge face, when the gravity-closing gate is opening, and to return in either direction towards the lowest neutral position on the angled hinge face, when the gravity-closing gate is closing, thereby allowing the swing hinge and gate assembly to be attached to either side of the guardrail opening, wherein the swing hinge assembly has a C-configuration with the upper hinge portion and the lower hinge portion each extending from the back portion with the angled hinge face of the lower hinge portion sloping downwards from the back portion, CHARACTERIZED IN THAT the hinge axis is oriented perpendicular to the angled hinge face and the swing hinge assembly having the C-configuration defines a first side and an opposite second side and comprises a first hole disposed through the upper hinge portion and a second hole disposed through the lower hinge portion, said holes extending through the swing hinge assembly from the first side to the second side, allowing the swing hinge and gate assembly (20a, 21a) to be attached against either of the first side and second side. a. a gravity-closing gate, wherein a portion of the gravity-closing gate comprises a hinge pin hole disposed therethrough; b. a swing hinge assembly configured to be selectively attached to a guardrail on a first side of a guardrail opening or a second side of the guardrail opening, to allow the gravity-closing gate to open in either direction by rising from a lowest neutral position, wherein the swing hinge assembly comprises: (i) an upper hinge portion comprising a hinge pin thru hole; (ii) a back portion connected between the upper hinge portion and a lower hinge portion, wherein the lower hinge portion comprises a hole formed therein, and wherein the hole is axially aligned with the hinge pin thru hole along a hinge axis; and (iii) a recess formed in the swing hinge assembly between the upper hinge portion and the lower hinge portion, wherein the recess comprises an angled hinge face of the lower hinge portion, sloping upwards into the recess in one or more directions, and wherein the recess opens outward from the back portion and receives the portion of the gravity-closing gate having the hinge pin hole; (i) an upper hinge portion comprising a hinge pin thru hole; (ii) a back portion connected between the upper hinge portion and a lower hinge portion, wherein the lower hinge portion comprises a hole formed therein, and wherein the hole is axially aligned with the hinge pin thru hole along a hinge axis; and (iii) a recess formed in the swing hinge assembly between the upper hinge portion and the lower hinge portion, wherein the recess comprises an angled hinge face of the lower hinge portion, sloping upwards into the recess in one or more directions, and wherein the recess opens outward from the back portion and receives the portion of the gravity-closing gate having the hinge pin hole; c. a hinge pin disposed through the hinge pin thru hole, through the hinge pin hole, and at least partially into the hole, thereby attaching the gravity-closing gate to the swing hinge assembly; and d. wherein the angled hinge face is oriented upward, whereby the gravity-closing gate rises in either direction away from the lowest neutral position on the angled hinge face, when the gravity-closing gate is opening, and to return in either direction towards the lowest neutral position on the angled hinge face, when the gravity-closing gate is closing,