Locomotive frames – With the engine’s frames erected, all the major frame stays, brackets, horn blocks, axle boxes & buffers have been cast and fitted using around 1,000 driven bolts.  With the tender tank undercoating complete it has been possible to remove the wheelsets from under the engine frames. This has permitted fitting of the remaining driven bolts and cold turned rivets in the outside motion brackets and the spring hangers.

We now have the profiles for the “shelf” under the back of the cab and Ian Matthews has started making some special tooling to facilitate hot bending of the 20mm thick plate to form the flanges on each end which mate with the outer Cartazzi frame plates. Normally, shaping like this is carried out cold using a brake press forming a series of small bends, however, the radius required in this case is equal to the thickness of the material necessitating the bending to be undertaken at red heat. In this condition the metal, which is 20mm thick,  will be sufficiently pliable to be bent using form tools in our 30ton press. As it is important that the finished article is a good fit between the outer frames, doing the work in house as opposed to by a plate bending firm will enable subtle adjustments to be made to ensure a tight and parallel fit.

The “shelf” bending jig – Leigh Taylor

When fitted to the frames, the shelf will complete the frame structure and enable Ian to start fitting the electrical trunking under the cab which is relatively complex as the 3D CAD view shows.

3D CAD view of the trunking on the shelf. – Alan Parkin

Tender – Steady progress with the tender frames continues at Ian Howitt’s works at Crofton. The initial machining of the hornblocks has been completed, the hornblocks dispatched to NVES in Darlington for welding on manganese steel liners (NVES, thanks to our activities over the years, maintain a welding procedure for welding manganese steel to cast or mild steel), and are now back at Crofton for final machining. Many details for the brake linkage and hand brake mechanism have been made including the brake cross stay and brake cross shaft.

Tender hornguides with manganese steel liners welded in place. – Daniela Filová

The hornguides being set up on the tender frames. – Ian Howitt Engineering

Alan Parkin has now produced several manufacturing drawings for the approximately 140 individual components which are required to fabricate the cylinder block. At the same time David Elliott is building up the scale 3D printed model to determine the best construction sequence to ensure that all seams can be fully welded. The intention was to issue a “request for expressions of interest” to a number of fabricators during December. The target is for an almost full set of manufacturing drawings at the end of January to enable shortlisted companies to quote for the whole job.

The latest cylinder CADs and the assembled scale model of the cylinder block. – David Elliott

In parallel with discussions are at an advanced stage with a specialist company in CFD (computational fluid dynamics) to model the steam flow through the cylinder block to ensure that we do not have avoidable pressure reducing features to enable us to optimize the detail of the design – there is little scope for significant redesign of the block as the steam and exhaust passages are already as large as practical within the tight limits of the envelope of the block, however some gains may be possible through increasing radii on the inner corner of bends etc.

It is expected that this work will lead on to a more extensive model to analyse steam flow from the regulator to the blast pipe which will assist in fine tuning the profiles of the cams and the diameter of the blast pipe tops.

A further use of CFD will be look at smoke lifting. The original P2 No. 2001 Cock o’ the North did not have smoke lifting issues as even at low powers, as students of the history of the P2s will be aware, but the second engine, No. 2002 Earl Marischal (as first built with Walschaerts valve gear and the same smoke box and smoke lifting plates as No. 2001), immediately suffered from drifting smoke affecting the driver’s view resulting in early fitment of large and rather ugly smoke deflectors. The main difference is that piston valves open and close the exhaust valves gradually, with very little cross section for gas flow at the start and end of each event resulting in the exhaust appearing to “leak” from the chimney encouraging it to stick to the boiler top, which with the cross winds and the Coanda effect draws the exhaust down on the leeward side of the boiler. By contrast, poppet valves open and close to full area quickly resulting in sharper edged exhaust beats. Whilst not a problem on No. 2001, with all the computer modelling to optimize efficiency and power, there is a risk that the “squareness” of 2007’s exhaust beats may end up less sharp. If a smoke lifting problem is identified it is anticipated that with 80+ years of aerodynamic development since No. 2002 appeared, some relatively unobtrusive aerodynamic fences or strakes could be applied to solve the problem.

A short-term lack of Solidworks drafting capability has been identified and steps are in hand to recruit addition resources to cover this to expedite production of the detailed drawings for the valve gear. Low risk items such as reversing gear, return crank gear boxes and cardan shafts, and casting and machining valve covers can then be put into manufacture. In parallel it is intended to prototype a cam/follower/tappet/valve assembly and subject it to some fatigue testing before committing to a full set.

3D CAD view of poppet exhaust valve. – David Elliott

Cylinder drain cocks – Considerable progress has been made (mainly by Ian Matthews) in installing Alan Parkin’s cylinder drain cock design onto the frames. The design is closely based on that on Tornado to eliminate the use of Bowden cables (as used on the original P2s).

Cylinder drain cock actuating linkages. – Ian Matthews

With the system design largely complete the Electrical System Specification has been updated to reflect all the new design elements.  A start has been made on writing the section on standards compliance, which involves a clause-by-clause assessment of relevant standards.  Many standards have been replaced since we designed the A1 so this represents a lot of new work.  We are also using the electrical system to pilot the Trust’s updated approach to risk assessment.  This is based on the new railway Common Safety Method for Risk Evaluation and Assessment (CSM-RA).  A first draft Hazard Log has been produced.  This describes potential safety hazards associated with the electrical system and lists causes, consequences and safety measures for each hazard.  A Risk Ranking is then allocated to each one and, where appropriate, additional mitigations are put in place.  The updated draft documents are currently under review by Graham Nicholas, the Trust’s Professional Head of Engineering.

Some of the structured electrical trunking and junction boxes. – Daniela Filová

Starting the turbogen on the A1 involves a manual process of warming through the turbine to expel water before running it up off-line and connecting the power supplies once it is operating at full speed.  DB Meiningen offers a control box which contains a circuit that uses the alternator tachometer output to determine when the turbine is up to speed before automatically connecting it to the batteries using relays.  However, this system is designed for direct battery connection.  The A1 system connects the turbogen via DC-DC converters, which is incompatible with the Meiningen circuit, so we have not used it on our engine.

As we are moving to a two turbogen solution for the P2 we are taking the opportunity to design our own start-up circuit, so the crew do not need to manually start and bring each turbogen online.  A prototype tachometer circuit has been designed and bench tested.  This will be used to drive a relay which will connect the turbogen to the loads once it is running above a pre-determined speed.  The next step will be to test this on the A1 when it is next in steam to confirm the optimum speed for switching.  The circuits will then be incorporated into the Turbogen Control Box system, which has already been designed.

The prototype tachometer set-up. – Rob Morland

Work on the new combined head/tail/marker lamp luminaire continues.  We have received the first driver PCBs back from Stevenage Circuits and Alan Green has built and tested an initial batch for use in finalising the design.  Roger Millington, Alan and Rob are now working together to ensure that the lamp performance when displaying each of the three aspects is optimised.

The initial delivery of driver PCBs for testing. – Rob Morland

For the rear of the tender we are planning to use two original Stones marker lamp housings to display the marker and tail aspects, as on the A1.  Provision will be made for fitting and connecting the new P2 headlamps to display the head aspect when running tender-first on the main line.  Alan Green has updated the A1 marker/tail driver circuit design to include modern driver components (the original design is now 12 years old!).  This will be compatible with the A1 lamps, so we will have replacement PCBs for those when they reach the end of their useful life.

We were delighted during the build of Tornado when supporters came forward and offered us original Stones housings that allowed us to fully fit the engine.  We now have a requirement for a further two housings for the P2.  We would be pleased to receive any offers of housings that will allow us to meet this requirement.  They need to be the same design as on Tornado and ideally have a clear lens.  Please get in touch if you have one that you would like to see fitted to the P2!

A Stones marker lamp of the type required for No. 2007. – David Elliott

Work on the electrical conduit system for the tender is currently paused, awaiting the next phase of work on the East Coast Digital Project, which we expect to include installation of the European Train Control System (ETCS) on Tornado.  As mentioned in TCC 58 we are taking the opportunity to incorporate several of the P2 electrical system design improvements into the design for Tornado, especially around the arrangements that permit cab removal.  Once this is agreed we will import the A1 design back into the P2 and complete the conduit work.

The A1 Steam Locomotive Trust has announced a new £40,000 appeal – The Turbogen Club – to fund the first of the two turbo-generators required to power the modern electrical system necessary for No. 2007 Prince of Wales to operate on the Network Rail main line.  To find out more and to join the club follow this link.

Significant progress has been made with all the major components being on hand the first boiler (the spare for Tornado and Prince of Wales) starting to look like a boiler. The boiler for No. 2007 is scheduled for delivery in December 2021 which is optimum for preparing it to be fitted to the locomotive around the middle of 2022.

Contemporaneously, Ed Laxton, our apprentice machinist, has almost completed machining the components for the regulator stuffing boxes and cross shafts, one set of which will be required to be sent to Germany in the not-to-distant future to enable completion of the regulator assembly and pressure testing of the first boiler. Following welding on the cranks on the cross shafts, they have been sent to Locomotive Maintenance Services (LMS) at Loughborough to have bronze built up on the parts of each shaft where the packing materials in the stuffing boxes bear. This reduces corrosion in this area and provides a bronze sleeve which when worn can be machined off and renewed without scrapping the cross shaft.  Photos courtesy of DB Meiningen.

By the end of November 2020, The Boiler Club fundraising campaign had recruited over 60% of its target membership with pledges of over £450,000. For further information download the leaflet here.

Following the initial delivery of motion components from Stephenson (Engineering) Ltd of Atherton work started on machining the four coupling rods.  The next steps included the completion of machining of leading coupling rods and the forging of the trailing rods which were heat treated and delivered to DLW on 10^th December.  In addition, by mid-December the inner connecting rod had been forged along with its strap and Stephensons had made a start on forging the outer connecting rods which means that by early 2021 the Trust will have taken delivery of all the heavy motion components.

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 photos show the forging of the massive middle connecting rod and a start being made on forging the outer connecting rods.  All photos courtesy of Stephenson (Engineering) Ltd of Atherton.

We continue to accumulate brake rigging for the engine, with the two trailing brake hangers and brake stay trial fitted to the frames. The two brake cross shafts have been delivered and Ed Laxton machined their bronze bearing bushes to enable them to be fitted to the frames.  The six leading brake hangers are a complicated shape necessitated by the coupled wheels on the P2 being very close together leaving no room for conventional brake hangers. After some discussions it was decided to start with profiles from thick plate to achieve the rough shape followed by a lot of machining to achieve the finished product. An order was placed some time ago, however the contractor, having procured profiles and started the machining, had a change in circumstances which prevented him finishing them. Kindly the part-finished profiles have been donated to the project, and Triple T Engineering at Newton Aycliffe are presently in the process of CNC machining them to their finished state.  All photos by Daniela Filová.

One of the two trailing brake hangers and brake stay fitted to the frames.

Ed Laxton machining a brake cross shaft bronze bush.

Part-machined brake hanger profiles.

Brake shaft bush in position.

Brake shaft in position.

The brake shaft and actuating lever in place.

The pony truck should has been delivered to DLW. The manganese steel hornblock liners have been welded, after which the main pony truck frame was re-mounted on the horizontal borer at North View Engineering Solutions in Darlington to have the hornblock liners machined to finished size. This completes the fabrication of the three major components of the pony truck.  In the meantime, Daniela is continuing to refine the FEA (Finite Element Analysis) stress modelling in collaboration with Ricardo Rail to produce the necessary supporting documentation to facilitate certification of the new pony truck design.  All photos by Daniela Filová.

The pony truck crosshead at North View Engineering.

Machining the pony truck on the horizontal borer at NVES.

The pony truck crosshead.

The machined surface of the pony truck.

Since last year’s announcement of the placing of a £1m order for two new Diagram 118 boilers from DB Meiningen (DBM) significant progress has been made and assembly of the first boiler is well underway.

A visit to DBM was made by representatives of the Trust on Wednesday 28^th October 2020. We are pleased to report that progress with both boilers continues and the work done to date is of a high standard, despite COVID-19 issues. Most of the detail components have been made and assembly of the first boiler is underway. The blanks plugging connections to the boiler, which are required for hydraulic testing, have been extracted from the stores at Darlington Locomotive Works (DLW) and sent to DBM.

Other boilers related progress to-date includes:

• Boilers order placed with DB Meiningen for delivery in early 2021 (spare to go onto Tornado at next overhaul) and late 2021 (to go onto Prince of Wales)
• Boiler detailed design study completed
• DBM completed detailed redesign of the banjo dome to ensure it fits under the P2 cladding; revised design for the dome submitted for stress analysis to FEA (Finite Element Analysis) specialists, CIDEON, who’s report confirms that the design is satisfactory
• 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

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 in 2021.

The first of the two new boilers being assembled at DB Meiningen – A1SLT

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.