High Steam Pressures.

The German State Railways (says the “Railway Gazette”), are at the present time experimenting with a 4-6-0 type express engine having a special boiler built for two working pressures, namely, 853 lb. per square inch in the rear or ultra-high pressure boiler, and 199 lb. per square inch in the boiler barrel proper. The inner firebox is formed by water tubes, the bottom ends of which reach into the water chambers of a hollow foundation ring, while their upper ends discharge into steam collectors. The system is filled with chemically pure water up to the tube ends in the steam collectors, and from the latter steam rises through vertical tubes to heating coils the firebox. The heat from the coils is absorbed by the water in the special boiler, and the condensate falls back to the foundation ring chambers through another set of tubes and thence starts the circulation over again. The working pressure in the firebox and heating coils is from 1,100 to 1,300 lb. per square inch.