"Engines" aside, for pure power (which is the deal for me really) you have to see a Blow-Through during the commissioning stage of a steam boiler. I was lucky enough to see loads back when Matla Power Station was being built. My dad used to take me in to work with him at the weekends. The blow-throughs were done in two stages. The first stage had a meter wide pipe sticking out the side of the building just above ground level, the second stage had 2 40cm pipes sticking out the building at the 16m (turbine floor) level. For those that don't know, the idea is to get the boiler up to operating pressure (around 16mpa), open the valves and send the superheated steam over to the turbine but then divert it just before it enters the turbine and dump it outside. The repetitive expanding/contracting of the pipework cracks off the rust and muck and the steam blows it out each time. Superheated steam at 16mpa exiting a pipe is something else!
