Re: SVRy 19 and 20

Well, as to those big cylinders, having to lower the pressure to compensate for insufficient weight on drivers (factor of adhesion), leaves you with a machine that is considerably less efficient.

There were a few pikes that were able to slightly raise boiler pressure, then sleeve the cylinders, resulting in about the same amount of power (t.e.) with resultant decrease in fuel use. One that comes to mind is the EP&SW with their Mikados that originally operated with 29" bores and 176 lb. pressure for a t.e. of 59,910 lbs. When this was later raised to 205 lbs., they were able to reduce the cylinder diameter to 27" and actually gained a tad in t.e., 60,500 lbs. And on top of that, they still had a factor of adhesion of over 4.0. Voila! The accountants must have loved this.