Steeple engine

[KC6OLD]

Can SOMEONE explain a "Steeple" engine(as on the WILSON G. HUNT) to me? But
please, be gentle, I'm still trying to get my mind "around" side lever.
Dave

[Dallinson]

Dave.
Steeple engine?
Let me try and give my best shot!!
Yes, this was one of Robert Napiers designs. He thought of it one night, got
out of bed, rolled back the carpet in his dining room and drew it on the
floor with the help of David Tod, who was summoned in the early hours.
It was first built and fitted to a seagoing steamer called “Clyde” in 1832.
Another engine of this type was fitted to a river steamer “St Mungo” in
1836.
Basically the cylinder is bolted to the bedplate with the piston rod
pointing upwards. Immediately above the piston rod is the paddle shaft. To
get around the shaft a yoke, or spreader, is fitted to the piston rod with
further rods that run up each side of the paddle shaft. They form a triangle
and meet at the crosshead, which is at the very top of the engine running in
vertical slots on each side. The connecting rod hangs down from the
crosshead to the paddle shaft crank. The steeple engine gets its name from
the tall pointed shape of the engine, that is a function of having the
narrow crosshead guides at the top.

A dictionary definition is “A vertical back-acting steam engine having the
cylinder beneath the crosshead”
(Whatever back-acting means??)
Hope that you get the idea and it helps.
David