A boarding bridge including: an inner tunnel walking deck which positioned above a floor of an inner tunnel with a space the therebetween, and forms a walking passage of the inner tunnel. An outer tunnel walking deck which positioned above a floor of the outer tunnel with a space therebetween, and forms a walking passage of the outer tunnel. The outer tunnel walking deck positioned at a height between the floor of the inner tunnel and the inner tunnel walking deck.

A boarding bridge including: an inner tunnel walking deck which positioned above a floor of an inner tunnel with a space the therebetween, and forms a walking passage of the inner tunnel. An outer tunnel walking deck which positioned above a floor of the outer tunnel with a space therebetween, and forms a walking passage of the outer tunnel. The outer tunnel walking deck positioned at a height between the floor of the inner tunnel and the inner tunnel walking deck.

A crawler bridge (10) having a bridge section (12) for bridging across opposite sides of a gap G. The bridge section (12) being connected to a support structure (14) which has a pair of elongate beams (16,17), that are spaced apart and generally parallel. The beams (16,17) each including leading and trailing feet (18,19). The bridge section (12) is attached to the beams (16,17) for relative movement forward and backward along the beams (16,17) and vertically up and down. The crawler bridge (10) has a first mode of operation when the leading and trailing feet 18,19 of the beams (16,17) are in engagement with a ground surface, in which the bridge section (12) is supported by the support structure (14) elevated above the ground surface and is movable forward and backward along the beams (16,17) and vertically up and down. The crawler bridge (10) has a second mode of operation when the bridge section (12) has been moved downward relative to the beams (16,17) and into engagement with a supporting surface, in which the leading and trailing feet (18,19) of the beams (16,17) are lifted away from the supporting surface and the beams (16,17) are movable forward and backward relative to the bridge section (12) and vertically up and down relative to the bridge section (12).

A crawler bridge (10) having a bridge section (12) for bridging across opposite sides of a gap G. The bridge section (12) being connected to a support structure (14) which has a pair of elongate beams (16,17), that are spaced apart and generally parallel. The beams (16,17) each including leading and trailing feet (18,19). The bridge section (12) is attached to the beams (16,17) for relative movement forward and backward along the beams (16,17) and vertically up and down. The crawler bridge (10) has a first mode of operation when the leading and trailing feet 18,19 of the beams (16,17) are in engagement with a ground surface, in which the bridge section (12) is supported by the support structure (14) elevated above the ground surface and is movable forward and backward along the beams (16,17) and vertically up and down. The crawler bridge (10) has a second mode of operation when the bridge section (12) has been moved downward relative to the beams (16,17) and into engagement with a supporting surface, in which the leading and trailing feet (18,19) of the beams (16,17) are lifted away from the supporting surface and the beams (16,17) are movable forward and backward relative to the bridge section (12) and vertically up and down relative to the bridge section (12).