Apologies in advance as I am sure this will have been discussed at some point but I'm wondering why Bulleid's pacifics all had their boiler pressure reduced from 280 psi to 250 psi during the 1950s. Was this purely to save on coal consumption or did it help to reduce wheelslip problems? As an aside, the Bulleids I am familiar with in preservation have all been downrated again to 225psi. Is this common across all preserved examples? If so was there some kind of engineering council that agreed to standardise on a lower figure or does this come from the railway inspectorate? Thanks!