Railroad bridges come in just about every shape and size, bridging the smallest streams to the largest canyons. Here is one of my personal home town favorites. This bridge now also exists in Model forum on Thomas Bontempo's P&LE route.
Here are a few shots of the prototype:
West side looking East

East side looking West

When this bridge was constructed between 1908 and 1910, the Army Corps of Engineers required any new bridges across the Ohio River at this point have a 700' unobstructed channel. The P&LE's Ohio River Crossing has a 769' unobstructed channel.

The P&LE's Ohio River Crossing was load tested before opening in 1910 with a total weight of 5,684,300 lbs. The bridge passed this load test with flying colors :)

My photos don't really do this massively impressive bridge justice. For me this bridge speaks volumes in regards to how the industrialist of the early 20th century felt about their future. This bridge was up to the task when the USA entered WWII. During this era the P&LE out hauled every other class one railroad in the United States (tonnage wise), earning the railroad the nickname "The Little Giant"
Regards,