All six coupling rods delivered

Funds raised to build new Gresley class P2 No. 2007 Prince of Wales reached £3.9m

We are thrilled to announce that all six machined coupling rods have now been delivered to Darlington Locomotive Works only seven years after the launch of the P2 project. The fundraising campaign to raise an initial target of £210,000 needed to pay for the manufacture of the heavy motion has also made good progress, with £178,000 plus Gift Aid already pledged by 178 supporters.

Despite the impact of COVID-19, progress on the construction of the new Gresley class P2 ‘Mikado’ continues to move forward rapidly. The engine has reached the condition where it is recognisably a P2 and the structurally complete tender tank and tender wheelsets are now at Darlington Locomotive Works. Construction and assembly work continue on all fronts, including boiler, wheelsets, tender frames, heavy motion, pipework and electricals. Design work for the extensively modified and improved cylinder block is complete, with the focus now turned to adaptation of the Lentz rotary cam poppet valve gear to further improve the original design.

The final pair of machined (trailing) coupling rods at DLW – A1SLT

The work involved in manufacturing the motion includes:

  • Redesign of coupling and connecting rods to use modern material as pre-war nickel chrome steel alloy proved prone to fracture
  • Incorporation of late-pattern BR-type continuous white metal lined crank pin bearing bushes
  • Use of the late-A1 design of inside connecting rod which overcame the tendency for the original design of inside connecting rods on LNER ‘Pacifics’ to big-end failure
  • Open die forging of six coupling rods, two outside connecting rods and the inside connecting rod and strap
  • CNC machining of all rods
  • Manufacture of oil box lids, coupling rod knuckle pins, nuts & washers and bearing bush keys
  • Casting of leaded gunmetal and phosphor bronze castings of crank pin bearing bushes
  • Machining and white metalling of bearing bushes
  • Fitting oil box tops
  • Assembly of bearing bushes to rods
  • Polishing rods.

In May 2018 the Trust placed a £181,000 order with Stephenson (Engineering) Ltd of Atherton, Manchester for the heavy motion. The order included the forging, machining and heat treatment of the nine heavy motion rods – intermediate coupling rod LH/RH, trailing coupling rod LH/RH, leading coupling rod LH/RH, outside connecting rod LH/RH and the inside connecting rod assembly (including strap, gluts and strap nuts and washers) – and the combined piston and rod.

Progress to-date on the heavy motion includes:

  • Six coupling rods: all six coupling rods have now been delivered to DLW; the intermediate coupling rods (between second and third coupled wheelsets) have been fettled, polished to a fine finish and fitted with white metal lined bronze bushes; the leading coupling rods (between first and second coupled wheelset) have also been fettled and polished to a fine finish; the trailing coupling rods (between third and fourth coupled wheelset) have both been delivered to DLW, both have had the tapered gradient pin holes lapped, one has been fettled and the other is being fettled
  • Two outside connecting rods: both have been forged and heat treated; machining is underway with delivery to DLW expected by the end of May 2021
  • Inside connecting rod and strap: the inside connecting rod has been forged, heat treated and is now ready for machining; the strap has been forged, to be followed by heat treatment and machining with delivery to DLW expected at the end of July 2021
  • Bronze white metal lined rod bushes: the first four bushes (for the intermediate coupling rods) were delivered to DLW from Locomotive Maintenance Services Ltd (LMS) of Loughborough in January 2021; LMS has the materials for the final four with an order expected to be placed over the next week
  • Gradient pins: the drawings are being finalised and will be made inhouse by apprentice machinist Ed Laxton

In April 2018, we launched a new appeal to raise the funds to manufacture the motion for No. 2007 Prince of Wales. The Motion Club was established with the aim of raising £210,000 from 175 supporters each donating £1,000 (plus Gift Aid) to the project in up to eight payments of £125 by standing order. The appeal started well and in just seven weeks it had already reached over a quarter of its target. Within three months, we had recruited over 140 members, with around £170,000 pledged, including Gift Aid.  To find out more and to join The Motion Club follow this link.

Mark Allatt, Trustee, The A1 Steam Locomotive Trust, commented, “We are delighted with the support the project to build Britain’s most powerful steam locomotive has received since its launch over seven years ago. With over £3.4m spent and around £3.9m donated to-date of the estimated £5m required, we remain on-track for completion within three years. However, to maintain this progress we need to raise £700,000 per year and we are still seeking to recruit members of The Motion Club in order to complete the funding for the heavy motion as well as additional ‘P2 for the price of a pint of beer a week’ regular donors or covenantors.”

David Elliott, Director of P2 Engineering, The A1 Steam Locomotive Trust, added, “The delivery of the final pair of coupling rods for Prince of Wales is a major step forward for the project, especially given the limitations of working during the COVID-19 pandemic. The machining of each rod by Stephenson (Engineering) takes around 100 hours. The next few months will see the completion of all of the heavy motion and the trial fitting of the coupling rods to the engine – creating the first tender-engine standard gauge ‘Mikado’ in the UK since 1945.”