90' Single-Track Railroad Through Girder Bridge -- Kit - 12-1/2 x 2-3/8 x 1-1/2" 31.7 x 6 x 3.8cm. The Walthers Cornerstone 90' Single-Track Railroad Through Girder Bridge kit is based on one of the most common North American railroad bridge designs. - Model Trains, HO Scale, HO Scale Layout Items