Blog Archive

Monday, November 9, 2015

Garratt 129 Progress


All the suspension components are now complete, and most have now been trial assembled on the engine units (above and below). This has been a useful exercise to prove everything fits together.....or doesn't in one particular case! It has also demonstrated that, despite the size of these locomotives, there is surprisingly little room to work, and clearances between parts are minimal.



With the ashpan outline design complete and mounting hole positions determined, the foundation ring has been drilled to accept the locating studs (above). Holes are currently being marked and drilled for the 3 fusible plugs in the firebox crown sheet whilst below, the main internal steam pipe has been delivered, and the weld-on end fittings are being turned.



Rolled steel flat bar for the new boiler crinolines has also been delivered, ready for spacer bars and end brackets to be welded in place. The crinolines wrap around the boiler, locating the insulation and supporting the cladding sheets. Below, the original firebox crinolines are in good condition and will be reused.



The biggest job currently is the manufacture of the brake rigging components for the boiler cradle and the two engine units (above). Below are some ends for the brake cross beams; the two on the right are partially machined from profile cut blanks, and the one on the left is to the final dimensions, ready to have the split cotter pin slot milled into it and the beam itself welded on.



The above photograph shows typical blank parts for one of the boiler cradle brake shaft hangers, along with the drawing.

Below is the blank for the hand brake arm. Whilst there is still a lot of material to be removed, these profiled blanks reduce the hours required for machining significantly compared to machining the whole thing from a square block of steel!



More brake parts; above are the pull rods which link the cross beams together, and below, the main brake cross beam plates on the right, and on the left, the cross heads which attach the pull rods to the cross beams. Again, all these are manufactured from profile cut blanks.



The existing brake hangers are being reused, however many of the holes are worn oversize. These have been welded up (above) and are being machined back on the CNC milling machine prior to new bushes being pressed in (below).


The next three photographs show progress on the boiler cradle, most of which is being carried out by the NG/G16 workshop day volunteers.


The smokebox support plate have been temporarily fitted to the frame ready to trial fit the boiler. Once the boiler is on, these plate can be adjusted by heating and bending until they match the radius of the smokebox barrel. They will then by tacked to the smokebox while the boiler is removed, followed by drilling and riveting in place.


The footplate cover plates have been drilled, mounting holes tapped, and the plates undercoated.


Work has begun on modifying the reverser stand; with the tapered section of the boiler cradle now further forward, the screw reverser  now sits over it, necessitating the fabrication of a new lower section to match.

One of the next major tasks will be to machine all the flanges for the steam and exhaust pipework, and fabricate the individual pipes ready to fit. In some cases, pipes need to be fitted prior to other components due to a lack of space. All the blanks for the flanges have been profile cut, and are seen below ready for machining.