Express Passenger Locomotive No. 36


Wheel arrangement:                              2-2-2

Leading wheels:                                    4’ 8”    diameter

Driving wheels:                                     6’ 3”    diameter

Trailing wheels:                                     4’ 0”    diameter

Wheelbase:                                           8’ + 7’ = 15’ total

Length:                                                 23’ 8”  over buffers

Height above rail –

        chimney cap:                                 12’ 8”

        boiler centre line:                           6’ 6”

Boiler –

        length:                                           11’ 11” between tubeplates

        tubes:                                           151 of 2 and 1/8” external diameter

        tube heating surface:                      1000    square feet

        firebox heating surface:                       60    square feet

        total heating surface:                         1060    square feet

        working pressure:                         80 lbs   per square inch

        firebox grate area:                         12·75   square feet

Cylinders (2, inside):                             15” diameter x 20” stroke

Weight:                                     22 tons 19 cwt



The frame is a typical Bury forged iron bar-frame with rectangular-section top members and round-section bottom trusses.


Boiler and Footplate

The firebox is the typical round pattern with a grate which is D-shaped in plan and with a ‘haystack’ domed top with sheet copper cladding; the internal firebox is made of copper with crown bar-stays.  The brass dome on top of the firebox carries two Salter spring-balance safety valves with levers pointing fore and aft; there are three water-level test cocks on the left side of the firebox, and a water gauge (glass tube and cocks are missing) on the right side.  Near the top of the firebox on the left side is a warming cock (the delivery pipe, for taking steam down to the tender water feed pipe, is missing); the regulator handle (throttle) is centred above the firehole; the diagonal rod behind the driving wheel, with its handle low down on the left side of the footplate, controls the ashpan damper; the large lever in a notched quadrant-plate at the right side of the footplate is the reversing lever.  This lever alters the steam valves via the expansion links of the valve gear to allow more economical running, and for reversing the engine.  There is no protection, not even a weatherboard, for the driver and fireman on the open footplate.


Valve Gear

The valve gear is Stephenson’s Link Motion with expansion links centrally suspended from a weighshaft mounted above the frame; the weighshaft carries a balance weight at each end, on short arms pointing forward, just behind the smokebox.  Horizontal valves above the cylinders are operated by valve-rods driven by rocking shafts; the lower arm of each rocking shaft engages directly with the pin of the die-block in the link.  The rocking shaft trunnions are fastened to the top of the slide-bars.


Tractive Effort

At 85% of working boiler pressure and with driving wheel diameter a nominal 6 feet, the tractive effort would be 4250 lbs.



The engine is standing on a length of the original GS&WR track of 1846: ‘bridge’ section rails weighing 90 lbs per yard, the heaviest then in use.



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