A vintage hand-made O-Gauge dura-aluminum railway girder bridge for your consideration in very good condition commensurate with age and use. Very durable -- would even stand up to outside use, I'm certain. The dimensions are:

Length: 18"

Height (inside): 4 3/4"

Height (outside): 5 1/2"

Width (inside): 5 1/2"

Width (outside): 6"

Weight: just shy of 3 pounds.