Railway bridges are a fascinating subject. The engineers who develop railway bridge types have the incredibly challenge of creating a thin piece of ground that can support thousands of tons of material moving at an incredibly fast pace sometimes hundreds of feet above the ground, with zero room for error.
On top of those impossible conditions, the particular area in which the bridge is needed presents its own set of requirements. Some railway bridge types involve shoring systems to meet a temporary needs. Some railway bridge types have to provide a means for foot traffic in addition to railway traffic. Some bridges support railways above, but also must be movable so that large boats