maximum steam pressure in locomotive boiler in bar
High-pressure steam locomotive Another way to avoid scaling in the HP boiler is to use steam alone to transfer the heat from the fire; steam cannot of course deposit scale. Saturated steam from an HP steam generator was pumped through HP superheater tubes which lined the firebox. There it was superheated to about 900 °F (482 °C) and the pressure raised to 1,700 psi (11.72 MPa). Only a quarter of this was fed to the HP cylinders; the rest was returned to the steam generator where its heat evaporated more water to continue the cycle.