definition
strict definition
trestle
A bridge or viaduct whose deck is carried by a continuous rigid support framework, often over many small spans.
A trestle is a span whose deck is supported by a continuous rigid frame, often forming a series of small bridges but generally acting as a single long support network for the deck above.
The supports work as a connected framework beneath the deck. A succession of short openings can give the appearance of several small bridges.
The form is defined by this continuous support network. It is not restricted to one construction material or to railway traffic.