Middleton Top winding engine house contains a pair of beam engines both driving a common crank geared to a winding drum around which the incline rope ran. They were built by the Butterley Company, near Ripley, Derbyshire, during 1828-29 and completed during December 1829. They are the world’s oldest rotative beam engines still on their original site and are both in very good condition.
Of the eight winding engines along the Cromford & High Peak Railway line, two comprised pairs of 10 horse power beam engines and the other six were pairs of 20 horse power engines, Middleton being of the larger type.
Each engine is a double-acting condensing (Watt-type) beam engine of 25 inch bore and 60 inch stroke controlled by a slide valve. Steam at 5 psi was admitted to the valve chest from the main steam pipe via a regulator type valve on each engine, enabling precise and rapid control. The cranks are set at 90 degrees to ensure that the engine would start from any position. The flywheel driven by the two engines is 16 feet in diameter and mounted on the crankshaft with it is a fifty tooth gear meshing with 150 teeth around the periphery of the winding drum below. The maximum permissible operating speed was laid down as 40 rpm (i.e. 40 strokes per minute) and, at that rate, a run on the incline would take only four or five minutes. The massive cast iron beams of each engine are supported on pedestals mounted on an iron transom rather than a "bob wall" which makes for a light and spacious engine house.
When the railway opened, all the inclines employed endless chains but when safe and reliable wire rope became available in the 1860's it was progressively adopted from that time. At Middleton though, due to the opening of a quarry halfway up the incline in 1857, which made double track operation difficult, together with a distinct lack of through traffic, it was converted to single track using direct haulage whereby 700 yards of rope was simply wound on and off the winding drum. This continued until 1894 when the London & North Western Railway (L&NWR), which had taken over the line in 1861, rebuilt the incline with double track for an endless wire rope and, at the same time, installed an idler wheel over the winding drum to prevent rope slippage. The fitting of this idler wheel is the only major alteration to the winding engine since its construction in 1829. The horizontal terminal wheel at the bottom of the incline around which the rope was guided is still in position mounted on its sliding wooden carriage which provided adjustment for the rope tension.
The original boiler or boilers at Middleton were described as being in poor shape by the late 1850's and were replaced by the L&NWR about 1868. The company installed a pair of Cornish boilers 22 feet long and 6 feet 6 inches in diameter, doubtless built at Crewe Works using plate of their own manufacture, and numbered 303 and 304. These continued in use for ninety years and are still in place but now lack their doors and other fittings and the shed which protected the boiler fronts has been demolished. Due to the condition of the boilers the engines are now run for demonstration purposes on air pressure.
In the vicinity are the remains of no less than three very old and rare waggon boilers which may well have originally been installed in the C&HPR’s engine houses.