The project to build Britain’s most powerful express passenger steam locomotive today announced that it had fitted the pony truck wheelset to new Gresley class P2 No. 2007 Prince of Wales meaning that a main line ‘Mikado’ was in existence in Great Britain for the first time since 1945. The rear Cartazzi wheelset was fitted in early 2018 and the eight 6ft 2in driving wheels in July 2018.

No 2007 (C) David Elliott.

The Gresley class P2 2-8-2 ‘Mikados’ were the most powerful express passenger locomotives to operate in the UK. They were designed by Sir Nigel Gresley in the 1930s to haul 600 ton trains on the arduous Edinburgh to Aberdeen route. Sadly, the design was never fully developed and they were rebuilt by his successor Edward Thompson into ungainly class A2/2 4-6-2 ‘Pacifics’ in 1943/4, and scrapped by 1961. The A1 Steam Locomotive Trust (A1SLT – registered charity and builders of famous new 100mph steam locomotive No. 60163 Tornado) is building the seventh member of this class at its Darlington Locomotive Works (DLW) over seven years, at an estimated cost of £5m through its P2 Steam Locomotive Company subsidiary. The project will demonstrate how the design can be fully realised through use of modern computer design techniques, enabling the new locomotive to deliver its full potential hauling passenger trains at high speed across today’s national network.

The Whyte notation for classifying steam locomotives by wheel arrangement was devised by Frederick Methvan Whyte in the early twentieth century. In the notation a locomotive with one leading axle (two wheels) in front, then four driving axles (eight wheels) and then one trailing axle (two wheels) is classified as 2-8-2 and commonly referred to as a ‘Mikado’. The name ‘Mikado’ originated from a group of Japanese type 9700 2-8-2 locomotives that were built by Baldwin Locomotive Works for the 3ft 6in gauge Nippon Railway of Japan in 1897. In the 19th century, the Emperor of Japan was often referred to as “the Mikado” in English and the Gilbert and Sullivan opera The Mikado had premiered in 1885 and achieved great popularity in both Britain and the USA. Although the most numerous wheel arrangement globally, only eight standard gauge ‘Mikados’ operated in Great Britain, two Gresley class P1 freight locomotives (introduced in 1925 and both scrapped in 1945) and six Gresley class P2s (introduced in 1934 and all rebuild by 1944).

The work involved wheeling the engine to create the first standard gauge ‘Mikado’ since 1945 include:

  1. Machining axle and cannon box castings, manufacturing roller bearing details
  2. Boring eight coupled wheel bosses to finished size
  3. Assembling bearings and cannon box onto pony truck axle
  4. Assembling bearings, cannon and axle boxes onto plain coupled axles
  5. Trial fitting coupled axles to frame
  6. Pressing Cartazzi wheels onto axle, fitting & machining tyres and fitting bearings & axleboxes
  7. Pressing plain coupled wheels onto axles, fitting and machining tyres
  8. Assembling crank axle, fitting bearings & axleboxes, pressing wheels onto crank axle, fitting and machining tyres
  9. Finish machining crank bosses & boring crank pin holes and machining & fitting all crank pins
  10. Trial fitting wheelsets to frames at DLW.

The wheeling of No. 2007 Prince of Wales was funded by 200 members of The Mikado Club of The A1 Steam Locomotive Trust who each donated £1,000 plus gift aid towards the project. The total cost of the wheeling, including all components, is estimated at around £400,000. A selection of wheeling-related parts – including a 6ft 2in driving wheel at £12,000 – are still available for sponsorship under the Trust’s Dedicated Donations scheme.

Progress building Britain’s most powerful steam locomotive continues at Darlington Locomotive Works and includes:

  • Frame plates for engine and tender rolled and profiled; engine’s frames erected at Darlington Locomotive Works; all major engine frame stays, brackets, horn blocks, axle boxes and buffers cast (44 in total); over 1,000 fitted and driven bolts ordered and delivered, approximately 800 now fitted to the frames
  • All 20 wheels for engine and tender cast and proof machined; roller bearings for all engine and tender wheelsets and engine axles (including crank axle), tyres and crank pins delivered, tender axles, tyres delivered, Cartazzi and coupled wheelsets complete
  • Preliminary discussions held with boiler manufacturers and forged foundation ring corners manufactured and machined; start made on boiler fittings with castings for combined injector steam and delivery valves
  • Study into ride and suspension completed using rail industry standard Vampire® software; finite Element Analysis completed on re-designed crank axle to ensure locomotive complies with modern standards; assessment and notified body appointed to oversee certification – first site visit made
  • Smokebox and cab substantially complete
  • Crosshead castings received
  • Boiler cladding trial fitted to engine frames
  • Tender frame construction under way, axlebox and other tender castings delivered from William Cook Cast Products, I D Howitt Ltd of Crofton near Wakefield commissioned to erect tender frame – many detailed parts made including front drag box and brake linkage, castings being machined
  • Nameplates and chime whistle delivered
  • Over £2m spent, £2.4m raised and £3.1m pledged of the required £5m.

Mark Allatt, P2 Project Director and Trustee, The A1 Steam Locomotive Trust, commented:

We are delighted with the level of support that the project to build Britain’s most powerful steam locomotive has received since its launch. Thanks to our supporters’ continued generosity, over £3m has now been donated or pledged.

“The fitting of all of the wheels to the engine and therefore creating the first standard gauge ‘Mikado’ in Great Britain since 1945 marks a significant milestone in the construction of No. 2007 Prince of Wales. Thanks to the dedication and generosity of our supporters, we remain confident that we are on-track for completion of new Gresley class P2 locomotive No. 2007 Prince of Wales in 2021.

“I would encourage all steam enthusiasts who haven’t yet contributed to this exciting project to help us to meet these deadlines by becoming a monthly ‘P2 for the price of a pint of beer a week’ Covenantor. It’s time to get on board! This year will see further major announcements as the construction of new Gresley class P2 No. 2007 Prince of Wales gathers pace.”

To become a monthly Covenantor, email, call 01325 460163 or visit for more information.

– ENDS –