(a) High speed engine—have speed of 250 rpm and more than.
(b) Medium speed engine have speed lying among 100 to 250 rpm.
(c) Slow speed engine have speed below 100 rpm. (iii) Based on Type of Steam Action Depending upon whether the steam acts on equally sides of piston or just on one side of piston engine can classify like double acting steam engine or single acting steam engine. Lest of single acting engine out of two piston strokes that is forward stroke with backward stroke, simply one stroke is use for work output. As in double acting engine equally forward and backward strokes of piston are use for work output otherwise that is extension of steam occur as of both sides of piston instead. In theory, it might be said that power develop as of double acting engine will be almost double of power develop as of single acting steam engine. Power productivity as of double acting engine is not precisely two times of output as of single acting engine as only one side complete piston face is accessible for action on other side piston face area offered for action is fewer due to existence of connecting rod, pin and so on. (iv) Based on Expansive or Non Expansive Type of Working The steam engine can be non expansive kind in which steam is inject all over piston stroke that is piston movement is cause due to high pressure steam forcing piston as of one end to further end all over and not due to extension of steam. Such kind of steam engines is call non-expansive steam engine. (v) Based on Type of Exhaust From Engine Exhaust as of steam engine might either go to atmosphere or to condenser. In certain applications where expansion in steam engine is extensive up to sub atmospheric pressure then exhaust steam as of engine is send to condenser. Such kinds of engine whose exhaust go to condenser are term as ‘Condensing engine’. Steam engines whose exhaust steam is send to atmosphere is call ‘non-condensing engine’. Steam engine of condensing type usually delivers steam at 0.05 bars in condenser. Steam change into condensate in condenser and condensate is send again to boiler through feed pump. Owing to lower back pressure in condense engine work productivity as of such engine is further. (vi) Based on Number of Stages Its depend upon the number of stages of expansion in steam engine, it might be termed as single stage, two stage, three stage, four stage engine and so on. (vii) Based on Number of Cylinders Steam engine may hold steam expanding in single cylinder with engine is call “simple steam engine”. Steam engine may contain expansion of steam occuring in over one cylinder for example expansion occurring in high pressure cylinder and low pressure cylinder et cetera. Such steam engine have expansion in over one cylinders in succession are term as “Compound steam engine”. Compound steam engine have three cylinders can contain one cylinder call as high pressure cylinder, second cylinder as intermediate pressure cylinder with third cylinder as low pressure cylinder. (viii) Based on Type of Governing Steam engine can contain different types of governing as throttle governing with cut-off governing. Engine may be call as throttle governed engine or cutoff governed engine. (ix) Based on Type of Application Steam engine perhaps of following types depending upon applications as;
(a) Marine engine
(b) Stationary engine
(c) Locomotive engine