The first of the large frame stays which have been re-designed as fabrications is presently being manufactured by North View Engineering Solutions in Darlington. This is the Frame Stay and Inside Motion Bracket.
Apart from holding the frames together, it also supports the inside cylinder slide bars. On the original P2 design it also had a saddle incorporated to support the front of the boiler where it joins onto the smokebox.
Apart from the decision to use Tornado’s shorter boiler causing the saddle to be in the wrong place, firmly attaching the back of the smokebox to the frames, in addition to bolting the front of it to the saddle on the top of the cylinder block gives the potential for cracks in the smokebox. This arises from the smokebox becoming much hotter than the frames when the locomotive is operating setting up severe stresses due to the smokebox expanding more than the frames.
Original P2 frame stay and boiler support
Modified stay for No. 2007
This problem was avoided with the A1 design by supporting the front of the boiler (and hence the rear of the smokebox) on a sliding foot to permit expansion. We are using the same arrangement for Prince of Wales. Meanwhile the next of the large frame stays, the Intermediate Frame Stay which as well as being redesigned as a fabrication has been modified to carry one air brake cylinder and an air pump instead of the original two vacuum cylinders has been ordered from North View Engineering Solutions.
Application of the Finite Element Analysis simulation package recently acquired to use in conjunction with Solidworks 3D CAD has indicated that the revised design has similar strength margins as the original, even with the addition of a 370 kg air pump.
The cab is making good progress with roof having been assembled on a specially made cradle, and the sides and spectacle panels added temporarily using bolts. Once the cab assembly has been proved, it will be completely dismantled and grit blasted and primed prior to riveting together. The profiled plate work for the cab is presently being rolled and pressed to shape.
The pattern for the chimney is making good progress at South Lincs Foundry at Spalding.
The front boiler support and pony truck top centre castings have been delivered following machining and have been trial fitted to the frames. The Cartazzi horn blocks have been removed from the frames and sent to North View Engineering in Darlington for adjustment and welding on the manganese steel liners. North View has also manufactured the Cartazzi horn stays.
Back at Darlington Locomotive Works the footplating has reached the stage where it has all been removed for grit blasting and priming prior to final fitting
North View has also started manufacture of the first of four large fabricated frame stays, the frame stay and inside motion bracket which apart from keeping the frame plates the correct distance support the inside slide bars.
Timsons Engineering at Kettering have been awarded our largest single machining order to date to machine all the engine axle and cannon boxes and manufacture all the spacer, abutment and thrower rings and details for the roller bearings and axle boxes.
Cab side trial fit – David Elliott
Fitting the spectacle plate to the cab side – David Elliott
Mick Robinson works on the cab – David Elliott
The whole assembly begins to take shape – David Elliott
Uprighted, the classic shape of Gresley’s wind-cutting cab is apparent – Bob Hughes
The major visible progress has been the delivery of the cab kit comprising laser profiles plates, rolled or pressed into curves where necessary.
The cab roof – David Elliott
The plate work for the smoke box has been ordered. Timsons Engineering at Kettering have started manufacturing the smoke box door frame – a complex shape being made by CNC machining from a piece of 90mm thick boiler plate. North View Engineering Solutions at Darlington have completed machining of the front boiler support and the pony truck top centre castings.
Back at Darlington Locomotive Works progress continues with permanent assembly of the frame stays and brackets, and on forming and fitting the footplating. As sections of the footplating are finished, they are dismantled, grit blasted and primed prior to bolting on permanently. Gritblasting removes mill scale from the steel work which saves many hours later when the paint finish is applied.
Progress with the footplating – Bob Hughes
Steve Wood has completed machining the buffer casings which are trial fitted to the front buffer beam.
Buffer casings in place – Bob Hughes
He has since turned the engine draw bar pin.
The engine draw bar pin – David Elliott
The first of the non-ferrous fitting castings have arrived at DLW, being injector valve bodies and handwheels and Cartazzi top wedges.
The first non-ferrous castings – David Elliott
Quotations have been received for the machining of all the engine axle and cannon boxes with their roller bearing spacers and thrust rings. An order for this work will be placed shortly.
The most significant item to have been manufactured recently is the smoke box door. Tornado’s smoke box door started life as a spun tank end which gave the dished shape. The sharper radius on the outside edge of the door was achieved by hand forging over a former. The “D” shaped smoke box door on the original P2 design does not lend itself to this method, although it would be technically possible to achieve it by cutting, black smithing and welding the round door, however with the smoke box door being both a prominent and iconic part of the P2 design, there was doubt that a satisfactory finish could be achieved by this method.
Other methods considered including CNC machining the door out of solid 8″ thick plate, however this was significantly more expensive that the method actually used. Having seen the quality and surface finish that South Devon Railway Engineering (SDR) was achieving with firebox back heads, throat plates and tube plates, they were asked to quote for making the smoke box door. After some discussion an acceptable quotation was received and male and female press tools made using the 3D CAD model.
Male and female smoxebox door formers at the SDR – David Elliott
Following a trial pressing in mild steel, the definitive smoke box door was pressed from Cor-Ten steel – the corrosion resistant steel used on unpainted metal bridges and sculptures such as the Angel of the North. For the first stage of pressing the plate was clamped flat over the female press tool and the domed male press tool pushed downward to dish the plate. The plate is then unclamped and re-heated and the flange round the edge of the door formed by pushing the male tool right through the female tool. The wavy edge is then cut off to leave an accurately shaped pressing. Sarah Anne Harvey’s photos show the process:
Further progress has been made with the footplating and driven bolt work. The machining of the coupled horn blocks is nearing completion. The cab “flat pack” has been ordered and the curved plates are in the process of being rolled or press-braked into shape.
The characteristic flowing footplate appears – David Elliott
Machined hornblock castings – David Elliott
Steve Wood bores a buffer housing – David Elliott
Mick Robinson torques a 1″ nut – David Elliott
Mick Robinson fits a dragbox wing plate – David Elliott
Injector valve body and hand wheel patterns – David Elliott
Cartazzi bottom wedge pattern – David Elliott
Front footsteps ready for welding to back plate – David Elliott
Footplate sections laid out to show where they go – David Elliott
Throughout Tornado’s intermediate overhaul and during subsequent months, work has continued in the manufacture and machining of components for No. 2007 Prince of Wales. Here is a selection of photographs showing recent deliveries to Darlington Locomotive Works.
Roller bearing canon and axle boxe castings – Tony Lord
Machined driving wheel castings – Tony Lord
Canon box and frame stretcher castings – Tony Lord
Mick removes the LH dragbox bracket for final fitting – David Elliott
Steve Wood machines a buffer casing – David Elliott
Some of the complex footplate sections are fabricated – David Elliott
The buffer beam and footplate angles are formed – David Elliott
Mick Robinson and Steve Wood trial fitting firebox front stay – Bob Hughes
Ian Matthews welding and grinding upper buffer beam strengthener – Bob Hughes
Ian Matthews welding and grinding upper buffer beam strengthener – Bob Hughes
Mick Robinson grinds burrs from firebox front stay – Bob Hughes
A significant moment! Mick reams the hole for the first permenant fixing – David Elliott
With the last of the earlier batch of frame castings now machined, progress is being made with permanently bolting them to the frames. To square up the frames, the bufferbeam stiffeners and the front buffer spring casings have been permanently fitted using the first of the 1065 driven and fitted bolts that have been acquired to assemble the frames.
Following experience with Tornado when we dismantled the buffer beam to bore the middle cylinder where some rust was found between the components, the decision has been made to “wet assemble” all the frame platework and frame stays. This is common practice in the aviation industry where sophisticated interfay compounds are routinely used in riveted aluminium alloy to inhibit corrosion. After looking at several options, we have settled on using red metal primer as the interfay compound, as where it is squeezed of the joints, it makes an excellent base to ensure adhesion of subsequent layers of paint. The sequence of photos shows Ian Matthews fitting the front bufferbeam. A coat of primer is applied to both mating surfaces and the components assembled and fully bolted together whilst the paint is wet.
Ian uses a torque wrench on nuts on the buffer spring casing – David Elliott
Bufferbeam stiffeners and buffer spring casings ready for bufferbeam fitting – David Elliott
Ian Matthews applies primer to frame stays – David Elliott
Ian applies primer to the back of the bufferbeam – David Elliott
Lifting on the buffer beam – David Elliott
Inserting driven bolts with a copper hammer – David Elliott
The buffer beam is on – David Elliott