zero

one

two

four

locomotive boiler

Babcock and Wilcox boiler

Stirling boiler.

all of the above

locomotive boiler

Cochran boiler

Cornish boiler

Babcock and Wilcox boiler

1 tp 1.25m

1 to 1.75 m

2 to 4 m

1.75 to 2.75 m

supplied by same manufacturer loose and assembled at site

supplied mounted on a single base

purchased from several parties and packed together at site

packaged boiler does not exist