About: Vertical cross-tube boiler

A cross-tube boiler was the most common form of small vertical boiler. They were widely used, in the age of steam, as a small donkey boiler, for the independent power of winches, steam cranes etc. The boiler has the advantage of simple robust construction, in particular requiring little regular maintenance. It is relatively inefficient, which was not a serious drawback to the purposes for which it was used. However it was also of limited heating surface, thus limiting its sustained output power, compared to other boiler designs. For that reason it was rarely used when power was required continuously, such as for locomotives. However as the boiler is of relatively large internal volume relative to its power, this acts as a transient reserve of steam. Applications such as cranes only require