Why are railroad trestles called trestles and not bridges?

Question

All good answers......can't really pick a best one....I'm gonna let it go to a vote....thank you all ....Iearned what I wanted to know

Answer 1

A railway bridge anywhere but the US looks like a bridge but especially  in the rural areas they made bridges out of wooden trestles because 1/ wood was readily available,2/it is a relatively quick way to construct a bridge,3/you can do it with relatively unskilled labor  whereas other types of bridges require skilled workers.

Answer 2

Because a trestle is not a bridge.  Bridges have a distinct span supported by abutments or piers.  Trestles are more-or-less continuously supported by many bents.    

If a bridge pier fails, the bridge falls down.  If a trestle bent fails, there are enough other nearby supports that the trestle is likely to remain standing.

Answer 3

Why is anything called what it is. Why is do you call it a railROAD when cars can't drive on it?

The answer to this and your question is probably because someone else called it what it is today, many years ago and we still haven't got the balls to try and change it.

Answer 4

A trestle sounds stronger than a bridge.

Actually pickle's answer says it well, short and to the point.

Answer 5

In typical bridge construction, you will have piers or bents that support the longitudinal, moment carrying members which are usually called beams, girders, joists or stringers depending on the layout and material used.  The piers and bents will typically be constructed only in the plane transverse to traffic and will not have connection from one substructure (pier) unit to the next.

A railroad trestle will be comprised entirely of wood and one bent or pier will be dependent on the next with longitudinal and diagonal bracing to support the longitudinal loads.  There will be no clear spans between piers.

In other words, in a trestle, all of the piers work together while in typical bridge construction, each of the piers will carry load independently.

Answer 6

If the railroad is supported by large braced frames, then it is called a "trestle."  Any other type is called a "bridge."  

The word trestle means "a braced frame serving as support."  

(Technically, an automotive bridge could be a trestle, depending on its design.)

Answer 7

because of the "leg" supports under it.  A trestle is a frame or support to hold something else.... i.e. - railroad tracks.

a trestle is a bridge, but it is a trestle bridge.  i imagine people have just shortened it to be known as a trestle.

Answer 8

Because a bridge generally has a solid top surface (like a road) where a train's trestles will be an open structure, usually with gaps between the railway sleepers, and no continuous surface on top.

Hope that helps, although some will call them trestle bridges, just to confuse matters.