Gresley P2 2007 group had monoblock cast.

hullmat991 · **Joined:** Sun Dec 28, 2014 11:12 pm **Posts:** 232

I saw this on Twitter where I've been following the group for a while, and thought it would be a neat thing to share since not many things from across the Atlantic seem to show up here all that often. I wonder if this construction technique the T1 Trust will also employ since both groups seem to be using a similar way of putting the frames together.
https://twitter.com/Gresley_P2_2007/sta ... 6608055581

PMC · **Joined:** Sat Oct 17, 2015 5:55 pm **Posts:** 2876

The story, including a very interesting and informative video: https://www.a1steam.com/p2monobloc#/

Edit: An update from last month. They have completed a lot of the cylinder block, and they are also building two new boilers at DB Meiningen in Germany, one for the P2 which is nearing completion, and one as a spare for the new P2 and the A1 Tornado, which is just now completing an overhaul, so that the boilers may be rotated between the two of them and not have locomotives out of service for so long: https://www.a1steam.com/Portals/0/TCC%2070_Web.pdf

Rob Gardner · **Joined:** Sat Aug 21, 2004 10:50 pm **Posts:** 576

I believe the 3 cylinder monoblock is a fabricated assembly. Impressive accomplishment. The 2007 is really coming together.

Rob Gardner

10stewi · **Posted:** Sun Oct 22, 2023 7:51 pm

As Rob states, this is a welded assembly, not a casting. They have shown a 3D printed model on their website that they used to plan the welding and assembly with, as some welds would be very difficult to access if done in the wrong order.

Howard P. · **Posted:** Mon Oct 23, 2023 8:18 am

Reading their website, and noting the vendors, it appears to be a combination of some smaller castings (perhaps the cylinder "barrels"), with the overall assembly (the majority of the piece) being a weldment, incorporating the castings. It's certainly an impressive piece of fabrication!

Howard P.

Overmod · **Joined:** Thu May 24, 2012 1:37 pm **Posts:** 2492

The logical approach here would be to make some of the more complex pieces as lost-foam castings, and then arrange to jig them in proper fixation in a gimbaled fixture (a modern improved version of the fixture Bulleid built for the Leader frames, with more than one axis of 'rotisserie' rotation, in controlled atmosphere. Each full=pen weld can then be done by appropriate means, with the assembly repeatedly gauged to ensure the product is in tolerance as fabrication proceeds.

Such a procedure would facilitate the use of laser keyhole welding for the heavier sections, a procedure that requires a fairly high degree of automated guidance to work properly, but that can easily make nonlinear continuous weldments.

BWills · **Joined:** Thu Feb 02, 2023 1:55 pm **Posts:** 80

didn't they have to cast a new cylinder block for the Tornado prior?