We are building a brand new P2 class steam locomotive, based on the original 1930s design, and developed for use on the modern rail network.
The Gresley class P2 ‘Mikados’ were the most powerful express passenger locomotives to operate in the UK. They were designed by Sir Nigel Gresley to haul 600-ton trains over the arduous Edinburgh to Aberdeen route.
The ultimate performance and economy of a steam locomotive is dependent on optimising the complete thermal system from the fire hole door to the top of the chimney. Assuming the boiler and smoke box are fundamentally sound, the most important areas for good design are the cylinders and valves.
The design and manufacture of the unique cylinder monobloc, delivered to Darlington Locomotive Works in autumn 2023, was the first step towards building the powerhouse of the P2. With that work complete, we turn our attention to the other side of that same coin: the valve gear.
Lentz poppet valve gear is a more efficient design than Walschaerts valve gear, which is commonly found on UK locomotives including Tornado. Lentz developed the concept by which an improved system of large passages, large areas through valves and suitably controlled valve events, would fully utilise the latent capacity of the boiler. Lentz poppet valve gear was fitted on the first P2, No. 2001 Cock o’ the North, and we will be taking this principle and applying it to the valve gear design for No.2007.
For manufacture and testing of the new design, we need to raise £300,000 - the first £50,000 of which will immediately go towards the building of a prototype and test rig. The Valve Gear Club seeks to raise these funds through donations of £1000, in a lump sum or smaller instalments.
