Further significant progress is being made on the locomotive’s motion. All the heavy motion components have now been ordered from Stephenson (Engineering) Ltd of Atherton and work started on machining the four coupling rods with the first pair delivered to Darlington Locomotive Works in September. The updated poppet valve gear design is almost complete with the first components in manufacture.
To date the intermediate coupling rods (between second and third coupled wheelsets) have been delivered and fettling has started to create a high standard of finish, white metal lined bronze rod bushes have been ordered and machining of one of the leading coupling rods is nearing completion.
The next steps will include the completion of machining of leading coupling rods and the forging of the trailing rods.
To finance all this progress The Motion Club was founded in May 2018 to fund forging and machining of the heavy motion, with a target of raising over £210,000 including Gift Aid, from 175 supporters each donating £1,000 in up to eight payments of £125. As of today, The Motion Club has reached the initial target of 175 members, who have generously donated over £200,000. For further information on how to become a member click here.
The following photos show the various stages of machining involved in finishing the coupling rods and the latest one being forged.
Whilst Alan Parkin has been developing manufacturing drawings for the cylinder block, David Elliott has resolved one of the more tricky design issues with the poppet valve gear. One of the unsatisfactory features of the original No. 2001 cylinder block was having the inlet and exhaust valves on opposite sides of the middle cylinder. As a result, separate ports were required from the cylinder to the valve chests which gave rise to excessive clearance volume. Clearance volume is the space in the cylinder and its associated ports that is left when the piston is at the end of its stroke and is usually expressed as a percentage of the total volume for the cylinder when the piston is at the other end of its stroke. This space is not good for efficiency as for each power stroke of the piston, the clearance volume has to be filled with steam which does little work on the piston. The best figures achieved with poppet valves are around 10%. The original P2 design middle cylinder had clearance volumes of around 14% at one end and 16% at the other – the difference being due to the slope of the cylinder in the block to enable the connecting rod to clear the leading coupled axle whilst the valves were almost horizontal to be in line with those on the outside cylinders.
To overcome this problem, the layout of the valves has been changed to mimic the outside cylinders with the inlet and exhaust valves together and in line with the centerline of the cylinder. This does create a challenge, as whilst the exhaust valves can be driven directly from the Driver’s side cambox (as on No. 2001), the inlet valves are on the other side of the engine compared with the cam driving them. After several iterations a pair of rocking shafts have been designed to transfer the movement of the inlet valve cam tappets on the Fireman’s side of the engine across to the inside cylinder inlet valves.
No. 2007 cylinder section drawing showing the clearance volume – David Elliott
Cylinder block section showing rocking shaft drive to inside cylinder inlet valve – David Elliott
3D printing – David Elliott has recently acquired a 3D printer. The first work undertaken is to reproduce all the individual parts of the cylinder block at 1:8 scale to ensure that the proposed weld sequence will actually work with sufficient access to achieve all the welds. It will also help prospective fabricators to understand the design when quotes are sought.
1:8 scale 3D printed cylinder parts – David Elliott
Shortly after the printer was first set to work, we were sorting out patterns for the regulator stuffing box that is needed to test the new boilers in Meiningen and were reminded that the cover pattern was missing. The 3D model was rapidly modified to include machining allowances and add “draft” to the edges and a pattern printed. This took the printer about 56 hours altogether – fortunately, provided it does not run out of plastic filament or suffer loss of power, it happily proceeds on its own until finished!
3D printing of regulator stuffing box cover – David Elliott
The printed patterns for the stuffing box – David Elliott
Although delayed by Covid-19, the pony truck frame is making progress at North View Engineering Solutions in Darlington. The main elements (frame and steering arm) have been fabricated and parts for the crosshead machined.
The modification of the pony truck from the original swing link side control to the later V2 class type of spring side control represents a significant design change in a safety critical part of the locomotive. Whilst we have done a considerable amount of work to ensure that the new design will be stable and safe, to certify the locomotive it will be necessary to have an independent review of the design. Ricardo Rail has been retained to carry out this work building on the Vampire ride and track force model which was commissioned from the Resonate (formerly DeltaRail) before the P2 project was formally launched and provided the basis for the new pony truck design. All photos byDaniela Filová.
When we launched the first of our new mini-clubs in April we expected that it would be popular, but The Pony (Truck) Club quickly went from to a trot to a gallop with our initial target of 20 members passed within the first few days.
For your chance to ‘win’ your exclusive rosette, you can become a member of The Pony (Truck) Club here.
Recent progress by Daniela Filová and North View Engineering Services has been impressive, despite the restrictions imposed by the Covid-19 outbreak. Reference to the CAD drawing will reveal where many of these components are destined to go on the completed truck. Photos by Daniela Filová.
Since last year’s announcement of the placing of a £1m order for two new Diagram 118a boilers from DB Meiningen (DBM) significant progress has been made.
We recently dispatched the regulator and pilot valve castings and forged foundation ring corners from Darlington Locomotive Works to Germany for incorporation into the new boiler. Further discussions have taken place between our engineering and operations teams and DBM to finalise the locations of the increased number of flexible stays in the firebox based on experience with Tornado’s boiler.
The recent design review went smoothly and will now be submitted to DBM’s NoBo (Notified Body) TüV for approval after which DBM will send the Trust complete copies of the Technical File which defines the design for perusal by various UK bodies that we have to notify or consult. Provided these organisations do not have any significant comments, the revised design will then be fully released for manufacture. The parts that have been manufactured to date will not be affected by any of the proposed changes to the design.
Other boiler related progress to-date includes:
Boiler design study completed
Forged foundation ring corners manufactured
Regulator and pilot valve castings delivered
Superheater header cast and machined
Superheater elements being assembled
Smokebox assembled and trial fitted to the frames
Chimney cast and fitted
Boiler cladding manufactured and trial fitted to frames
Boiler order placed with DB Meiningen for delivery in 2021
DBM has completed the detailed redesign of the banjo dome to ensure that it fits under the P2 cladding
Revised design for the dome has been submitted for stress analysis to FEA (Finite Element Analysis) specialists, CIDEON, who’s report confirms that the design is satisfactory
Completion of the detailed design
Following on from this leap in progress, we would like to encourage those who haven’t yet joined The Boiler Club to help us fund the purchase of No. 2007 Prince of Wales’most expensive component. We must reach our 300 members target in2021. You can join The Boiler Club here. Photos by Christopher Wörfel, DBM/A1SLT.
The drilled firebox tubeplate
A detail of the above image
One of the coned sections showing the perforations for the banjo dome steam collector
Dome top covers
One of the foundation ring corners awaiting welding
The Foundation ring with all four corners tack-welded in place
We recently launched a £20,000 appeal – The Pony (Truck) Club – to fund the construction of the leading pony truck for No. 2007 Prince of Wales. We set a minimum target of 20 generous supporters willing to donate £1,000 plus Gift Aid (in up to four payments of £250) but this club has galloped away and more than 20 supporters have already signed up. We have therefore decided to extend the club by a few members to cover the considerable certification costs associated with the modified pony truck design. Please consider joining The Pony (Truck) Club in advance of the frame’s delivery to DLW, you can find details here.
The latest CAD drawing of the revised pony truck arrangement for No. 2007.
North View Engineering Solutions in Darlington are making progress with the pony truck fabrication, although this has been slowed by the COVID-19 issue. In the meantime the pony truck cannonbox has been temporarily assembled on the wheelset bearings using a set of trial fit adjustment rings (originally made for when the similar process was carried out on Tornado’s bogie wheelsets). Daniela Filová has measured the end float of the cannonbox which enables us to calculate the required thickness of the permanent adjustment rings to provide the Timken recommended end float and to ensure that the cannonbox is centred on the wheelset. All photos by Daniela Filová.
Pony truck wheelset on its end for measuring the cannonbox end float.
During this time design work on the P2 continues. Below you can see the cylinder block 3D CAD image, as at present, designed by David Elliott. The second image shows an interesting ‘skeleton’ view of the welds that will be used. The 3D CAD design of the cylinder block and valve gear is now substantially complete; further progress has been made in applying the weld details to the cylinder block inside exhaust passages. Particular attention has being paid to the order of fabrication to ensure that all welds can be completed properly.
Alan Parkin has rebuilt the 3D model of the cylinder block to make it more manageable – this has meant the total file size has now grown from around 25mb to over 250mb! The finished block will weigh approximately five and three quarter tons and will include a quarter of a ton of weld.
Although The Cylinder Club has reached its target and been closed, The Motion Club is still open and just another 15 members would see it reach its anticipated total as well. You can join The Motion Club by making a single donation. This form confirms your personal data and your £1,000 donation – please DOWNLOAD, print out, complete and return it to us with a cheque for £1,000 made payable to “A1 SLT – P2 Construction Fund” at the address shown. To pay by credit card, please contact the office on 01325 460163 or email .
You can also join The Motion Club by making multiple donations by Standing Order. This first form confirms your personal data and the amount that you would like to donate – please DOWNLOAD, print out, complete and return it to us at the address shown. This second form confirms your bank details, please DOWNLOAD, complete in full and return it along with the monthly donation form, we will then forward it to your bank.
In addition to the design work of the cylinders themselves, work has been progressing on the production and assembly of the cylinder drain cock gear. For those unfamiliar with these, the drain cocks overcome an inherent problem with steam locomotives, that of water condensing in the cylinders themselves. Since water doesn’t compress well, starting a piston-valve or poppet fitted locomotive with water in the cylinders can result in significant damage. To allow this water to escape steam locomotives are fitted with manual (sometimes steam operated) drain valves, three per cylinder, actuated from the cab by the locomotive crew. The drains are normally left open when the locomotive is standing and for the first few revolutions when it starts moving, allowing egress of any condensed water, hence the clouds of steam in front of British locomotives when they initially start moving (US and European locomotives often have the valves aimed outwards from the cylinder). In addition the cylinder ends are usually fitted with a pressure relief valve but this is designed to release excess steam rather than water. To operate all three sets of drain valves simultaneously, cross shafts and a linkage back to the cab are required, all of which have to be fitted between the locomotive’s frames or along some other route from the front of the engine to the lever in the cab, in this case on the fireman’s side.
On Monday 23rd March the newly grit-blasted tender tank was delivered to Darlington Locomotive Works, unloaded onto the Matterson jack spreader beams and duly mounted on the recently acquired and re-furbished accommodation bogies. All photos and video by Daniela Filová
You can find out more about The Tender Club and how to join it here. Please help fill it up!
The tender tank has been finished at North View Engineering Solutions (NVES) and exhibits much flatter external panels than those on Tornado’s tender when it had reached this stage – it will now be delivered to Darlington Locomotive Works (DLW). Ian Howitt has made further progress in making small parts for the tender frames and Ian Matthews has completed filling and priming/undercoating the tender wheels. All photos by Daniela Filová except where stated.
Brake pull levers take shape at Ian Howitt’s engineering works – John Taylor
The tender springs arrive at DLW
The tender at NVES
David Elliott supervises the hydraulic test of the tender tank
The tender was then grit-blasted at NVES by Ian Matthews