- fish-bellied girders
- • греда с еднакво съпротивление на огъване• греда с рибовидна форма
English-Bulgarian polytechnical dictionary . 2013.
English-Bulgarian polytechnical dictionary . 2013.
Permanent way — The permanent way means the physical elements of the railway line itself: generally the pairs of rails typically laid on sleepers embedded in ballast, intended to carry the ordinary trains of a railway. This page describes British practice and… … Wikipedia
History of trams — Tram systems were common throughout the industrialized world in the late 19th and early 20th centuries, but they disappeared from many cities in the mid 20th century. In recent years, they have made a comeback. Many newer light rail systems share … Wikipedia