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