Transport Tycoon Deluxe

Trusses are OVER the train
Could be black, dark red, brown, blue, white even.

Here's one, another one, another one

Trusses are UNDER the train
Could be black, dark red, brown, blue, white even.

Here's one

Japanese suspension bridges tend to have very clean, trim lines and are in a light color such as white.

Seto Ohashi Bridge between Honshu and Shikoku islands

These are very common and everything from the Shinkansen to local trains run on them. Usually white or light gray in color.

Here's one

Here's another one