machines which I have made, am making, or intend to make, and some other stuff. If you find this site interesting, please leave a comment. I read every comment and respond to most.

Category: Big steam engines

The Most Powerful Steam Engine in the WORLD (?).

Excluding nuclear powered steam turbines and some others.  But 12,000hp is not to be sneezed at.

At Sheffield’s  Kelham Island Museum  we (Jennifer Edwards, a blog reader of, and I), saw a steam engine which was big, but not as big as the triples at Kempton.  So how can it be “the most powerful etc”.

Well, it is a triple, but not a compound triple.  It is a simple triple.  Double acting.  so each cylinder puts out power like it is the HP cylinder of a triple expansion engine.  It must be a prodigious consumer of fuel and energy.

Why so much power requirement?  Well this engine was used to power a rolling mill, to curve the armour plating of battleships.  Plates up to 16″ (400mm) thick.  The steel was red hot while this was being done, and the plate was rolled back and forth until the desired curve was reached.  Several re-heatings of the plate was required until the desired curve was achieved, so it was important that as many passes as possible were done in the shortest time.  So this engine is capable of full power reversals, very quickly.  Unfortunately there was insufficient room in the museum to fit the rolling mill.


This large crucible sits at the Museum entrance.  (Jennifer for scale.)

And we saw that happening today.   It was very impressive, and apart from some clanking of the huge spur gears, very quiet.


Cylinder bores 40″,  stroke 48″, installed 1905, used until 1976.


50 ton flywheel


And pinion


Reversing gear


Current modern boiler is no match for the original 10 Lancashire boilers.


The demonstration lasted only 3 minutes, before the large gas fired boiler ran out of steam at 100psi.  And they had been heating the boiler since yesterday.  Under industrial use, 160psi was used.

Jennifer is trying to obtain some plans to model the engine.  Hmm…I might have discovered my next model too…

Big Triple Expansion Steam Engines

I knew that the triple expansion engine at Kempton Pumping Station would not be steaming today, but I wanted to see it anyway.


It is sited next to the Thames, and pumped water from the river up to a holding reservoir.

As I walked to the building I could see the outlines of the huge engines through the windows.

But it was closed!  Damnation!

But, a kind volunteer, hearing how far I had travelled, let me in, and gave cart blanche to wander at will.


There are two of these 63′ high monsters.  This one has been restored, and is run on steam occasionally, after the boilers have been lit for 48 hours.  The other engine is currently being restored.  The crankshaft of the second one was rotated with the barring engine about half a revolution, after no use since 1985.  Of course it is a triple expansion steam engine, and it now is run on a newish boiler which is gas fired.  Unfortunately the old Lancashire (?) boilers were scrapped.

The interior of the building is also interesting.  The walls are glazed bricks which look like tiles, and there is a 20 ton gantry crane.  The engines weigh 1000 tons each, so must have been assembled on site.


The walls are glazed bricks.  Note the piston rings on the walkway.

Below the engines are huge water pipes, pumps and valves.


The space between the triples is occupied by two steam turbine driven pumps, about which more in a later post.  The space was originally intended to be occupied by another triple, which never occurred.   Interestingly, the triples are mirror images of each other, rather than identical, which means that a lot of components cannot be interchanged.  It probably made the plans more symmetrical and elegant.  Very British I suspect.


Hey, that’s me.  In my tourist hiking gear


Overall engine height 62 feet (18.9 meters)



Monster big ends and cranks


HP gauges.  Beautiful artwork hey Frank?!


And aren’t those column bases works of art?


Barring engine.  Steam powered


Those are my fingers against the flywheel, and teeth for the barring engine.


One of many oil distibutors


Right on top of the LP


Piston rod and crosshead


On top of the world


Looking down to a big end and the crankshaft


Big machines need big nuts


The HP cylinder


A volunteer pointed out that some of the safety fence posts are recycled Boulton and Watt parallel motion bars!


check out those cylinder diameters and clearances!


Spare piston rings


Piston ring, my finger


Piston ring join.

I am rapidly running out of posting space, despite many more pics.  So I had better pause.  I didn’t get to the turbine engined pumps.  But I have many more photos…

Let me thank the very kind volunteers who spent time with me to talk about their engines at Kempton.  A marvellous experience.  I must return one day to see them under steam.