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Crémaillère
A crémaillère is a French, mechanical term for the rack, or a straight bar with teeth on one edge designed to work into the teeth of a wheel or a pinion (French pignon) that predates the Renaissance. The term was generally applied in English to engineering applications which had notched, toothed or drilled surface, even when only visually so, such as the edge of the staircase. The term is also applied to the rack railway. During the 17th to 19th centuries, the term was widely applied to lines of entrenchment usually formed in a saw-tooth pattern, known as indented lines, particularly during siege A siege () . is a military blockade of a city, or fortress, with the intent of conquering by attrition, or by well-prepared assault. Siege warfare (also called siegecrafts or poliorcetics) is a form of constant, low-intensity conflict charact ...s. These lines are usually employed on banks of rivers, or ground which is more elevated than, or which commands, that of the enemy. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rack Railway
A rack railway (also rack-and-pinion railway, cog railway, or cogwheel railway) is a steep grade railway with a toothed rack rail, usually between the running rails. The trains are fitted with one or more cog wheels or pinions that mesh with this rack rail. This allows the trains to operate on steep gradients of 100% (45 degrees) or more, well above the 10% maximum for friction-based rail. The rack and pinion mechanism also provides more controlled braking and reduces the effects of snow or ice on the rails. Most rack railways are mountain railways, although a few are transit railways or tramways built to overcome a steep gradient in an urban environment. The first cog railway was the Middleton Railway between Middleton and Leeds in West Yorkshire, England, United Kingdom, where the first commercially successful steam locomotive, ''Salamanca'', ran in 1812. This used a rack and pinion system designed and patented in 1811 by John Blenkinsop. The first mountain cog railw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
