Much earlier than the BESA. That is an E1 class.

precisely. [link]


Heavy is wishmaking fairy.

As pertaining to locomotives, nicholson thermic syphons operate on the principle of drawing cold water through a small tube into an anti-venturi, a very large heated area. This results in a rapid suction of cold water away from the coldest point in the boiler, the throat sheet, and draw it up to the crown. These types of syphons were commonly made of copper and consist of a tube that draws back into the shape of two sheets that are stayed together much like the water walls of a traditional firebox. They join the crownsheet at the top, they or the equivalent of (such as the upwards flow circulators in 611's firebox) are really a must for any modern steam locomotive.

Desmodromic poppet valves are not different at the valve seat or geometry in any way from regular poppet valves be them on a steam engine or IC engine; it simply means that the valve closure is achieved with the same lever it was opened with or a seperate mechanical lever linkage so the closure is positive, as OPPOSED to a poppet valve that is opened by a lever action that fights a spring, and then is closed by that same spring. Desmodromic poppet valves are commonly found on the air sides of large air compressor steam engines and are actuated by corliss latches. Semi desmodromic valves were also used, meaning that there was a lever that took tension on and off of the closure spring so that the valve did not have to fight the spring as well as the air pressure when it needed to open, but would always shut at the proper time.



Hope this helps!