how is it monitored?
A pressure gauge, a sight glass and a governor.
Steam engine
For safety reasons, nearly all steam engines are equipped with mechanisms to monitor the boiler, such as a pressure gauge and a sight glass to monitor the water level.

Many engines, stationary and mobile, are also fitted with a governor to regulate the speed of the engine without the need for human interference.
what is nsb el 9? It is a retired class of three electric locomotives. who built it? Thune. who is he? They are a Norwegian manufacturing company. when was it founded? 1815. who were its founders? Anders Paulsen Thune. what can you tell about their history? Started in Drammen, produces agricultural machinery and steam engines. The factory expanded to Skøyen in Aker in 1901. tell me more about the latter It is a heat engine that performs mechanical work using steam as its working fluid. can you explain its steam turbines? It was the final major evolution of the steam engine design as they are more efficient than reciprocating piston type steam engines.
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Steam engine [SEP] Monitoring and control
The steam engine indicator traces on paper the pressure in the cylinder throughout the cycle, which can be used to spot various problems and calculate developed horsepower. It was routinely used by engineers, mechanics and insurance inspectors. The engine indicator can also be used on internal combustion engines. See image of indicator diagram below (in "Types of motor units" section).