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OVERHAUL 2015 - 2022

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Sir Nigel Gresley is now out of traffic for overhaul. This will probably take six to seven years and cost about £750,000. If you would like to make a donation towards this overhaul please click on the the donate button.

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Notes from information supplied by Darrin Crone, Locomotive Engineer.

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Although work has stopped at York there will still be updates of work that continues to be done at various places off site (Note: off-site work only undertaken where fully compliant with all Government guidance).

From July 2021.

26 July 2021

With the platework complete on the tender, painting has advanced well. The inside of the vestibule is now painted to top coat, which will allow the vestibule door to be fitted.

In the coal space the last of the unpainted surface under the left streamlining was wire brushed and painted to primer. Primer has also been applied all round the coal space.

The back of the tender front plate has now been painted to undercoat and the front of the coal space division plate.

A lot of hard work has been put into the corridor with a lot of the prep and priming. The left side where the GSMR trunking runs is now to top coat so that the GSMR refitting is not delayed. The rest is now in undercoat.

The tender front has now been painted to top coat. The corridor connection face plate has also been painted black.

Up on the water filler lid the material thickness around the hinge has been built up with weld where it has wasted. The lid hinge has been fitted with a new pin. The area around the water filler has been cleaned out and given an all over coat of black gloss..

Under the front of the tender the installation of the water feed valves has been completed after space was found to provide clearance against the air and brake pipes that crowd the area.


The water supply to the valves is piped from the sump. On the bottom of the sump is a banking plate and cap through which the sump can be drained. The plate was refitted and the cap retrieved from store and fitted.

With the water valves in place a start has been made on making new water handle shafts. The bottom of the shafts have boxes that fit over squares on the top of the valves. Square section material was used to give the square shape to the box, and the sides made up of 2 angles. The squares were welded to the ends of the shafts after preps were machined. The shafts were fitted on to the valves and the handles are now being fitted to the tops of the shafts. This requires the circular shaft tops to be made square to tightly locate in the existing handles. One handle is shorter than the other to miss the water scoop gear.

The handbrake bracket has now been refitted to the tender front. The new handbrake shaft was tried in and the hole in the new floorplate trimmed to provide plenty of clearance.

The handbrake shaft is prevented from lifting by a locking ring fitted under the handbrake bracket. This is secured by a taper pin. The hole in the new shaft needed to be remade and this has now been done. A suitable taper pin is fitted and the handbrake is ready for reassembly.

The main intermediate coupling bar received during the last report has been dimensionally checked OK and is now receiving hand finishing to blend machined radii and to remove machining marks.

In preparation for the fitting of the intermediate draw gear the inside of the tender leading dragbox has been painted around where new bushes were put in for the side link pins.

The main intermediate drawbar bolt that passes through the tender leading dragbox and is pinned to the main intermediate drawbar has been refitted. There is a large rubber spring fitted to the bolt and its spring rate tested and the spring is compressed in the assembly to provide the correct pre-load. A special washer was skimmed to size to provide the preload.

At the back of the tender the packing pieces to constrain the side movement of the gangway has been set. Special attention has been paid to this to ensure that the lower support rods are constrained so that there is no chance of them contacting internal pipework.

On the top of the gangway a new rubber cover has been cut and will be secured with steel strips bolted through the rubber. A couple of new retaining strips have been made and are painted ready for refitting. Some of the vestibule holes to take the strip on this side of the rubber are already drilled. Work is on going.

The assembly of the GSMR rack in the tender vestibule has been completed using new fasteners to the correct original spec, except we have now used stainless steel. The GSMR trunking that runs along the corridor has been refurbished and painted to top coat and is ready for installation. As the tender front is now painted to top coat the GSMR radio enclosure has been refitted and radio unit fitted.

Also on the tender front the electrical supply conduit up the front of the tender to the battery box has been fitted.

Work continues on the boiler cladding with the 4 panels over the firebox now fitted. One of the panels had the spine holes running off the edge of the cladding plate so a new strip was welded on to provide an equal flange distance. The panel backs were painted to top coat before fitting to give maximum protection against corrosion. The insulation has been cut back around the boiler washout and inspection doors so that the cladding "top hats" can fit close to the outer wrapper. Before the boiler bands are finally fitted they have been loosened and the cladding panel edges below painted to top coat.

The inside of the streamlined cladding access doors have been painted to top coat ready for refitting.

The outer dome cover has been needle gunned after the Painting Team leader over-ruled the Locomotive Engineer who thought only a rub down was necessary. The cover was tried on the cladding and its orientation determined. The securing holes have been tapped out.

The middle piston has been fitted with its rings and refitted. The rings were gapped and during the process a stray weld was found on the cylinder liner, which it must have got during the overhaul, perhaps when the bogie stretcher overhaul was done. The weld was carefully removed, the rings were then fitted to the piston and the piston put in. The piston gland assembly was fitted after gapping the packings. Finally the cylinder cover was fitted.


The middle piston rod has been put in its crosshead and the large cotter fitted.

The middle piston rod has been put in it's crosshead and the large cotter fitted.

All the piston travel limits were checked, called the bump stops. The slidebars and crossheads are marked showing where the bump stops were found in the past and reassuringly they match well what we have found this time. When the left was initially done this wasn't the case. The very end of the crosshead just contacted the run out on the slidebar. The crosshead whitemetal was chamfered and now it matches the bump with clearance on the slidebar.

The middle leading valve cover has been put on and the valve crosshead fitted and linked up to the Gresley gear. The trailing valve cover and tail rod cover were fitted. The tailrod cover has a clack on its oil feed, which was inspected and lapped, then fitted.

Some easing of the Gresley gear pin holes was done. The pins are now all finally fitted and cottered and grease nipples fitted.

When the loco was modified during the second world war to increase the valve travel the slots through which the 2:1 and 1:1 levers pass through the frames were lengthened by flame cutting. As we have now very carefully levelled and aligned the gear the 2:1 lever comes very close to a lump in the cut out. This has now been removed to prevent any possibility of the gear contacting the edge of the cut-out.

The outside valve guides and glands have had their lubrication pipework installed.

Special taper pins for the valve gear have been ordered. Initially the gear would have accepted standard pins but after repeated cleaning of the holes of wear, standard pins won't fit and specials are required. With a very slight taper a small increase in the diameter of the hole makes a big difference to where the pin fits, and it must project each end of the hole.

The spherical ball bearings in the return crank rods have been fitted. One is a new bearing, the other being ex-service and suitable for further use. It was found that in the right bearing fit was very tight. Upon measurement the housing was found to be out of round so was carefully dressed until the bearing entered satisfactorily and the bearing rotated easily. Interestingly this was the location of the bearing found to be damaged at this overhaul.

The return cranks were fitted to the rods and have now been fitted to the loco. They will require removal when the connecting rods are refitted, but will be examined as they rotate when the loco is pushed on to the wheeldrop in the coming weeks to ensure there is the specified clearances between crank and rod.

The bogie stretcher has a cover plate which no longer fits due to the new plates welded on to the bogie stretcher. The existing cover is now being cut and refitted to the stretcher in 3 parts. The original arrangement of single piece cover was not satisfactory as it prevented access to the oil pipes going to the bogie in service and was difficult to remove due to pipework and the drain cock linkage that runs closely over the top.

The Piping Team have also been working in the cab. The large vacuum train pipe from the ejector (drivers handle) to under the cab floor is now refitted using a new cone for the air ministry joint, made by an Engineering Team volunteer.

The Piping Team Leader identified that a plate passes over the vac. T.P. and that it is attached to the reverser stand. The plate has previously been painted and is ready for fitting and the stand had two loose bolts to take the plate. The bolt holes in the stand are reamed 3/4" and are amongst a set of fitted bolts designed to rigidly fix the upper and lower section of the stand. Drawings confirm this. The loose bolts were 5/8, one square headed other hex, ie looked to be what was available last time the assembly was put together. So it was decided to put the assembly back to as originally fitted as far as possible, and as confirmed by the 2002 overhaul photo record. As the stand is now assembled it is only possible to fit one as a bolt, the other as a fitted stud, nutted either end. These are now in place. It may not now be as easy to fit this plate but the assembly will be correct.

On the other side of the cab the steam heat pipe that runs from the manifold has been re-routed to take the new steel section that comes through the floor away from the damper operating handle. This required heating and reshaping the pipe as it previously weaved its way round the steam supply pipe to the air pump.

The new steam heat pipe below the cab has been shaped and left overlong for now to meet the copper pipe in the cab.

GA Drawing

The cylinder release valves are now all fitted and their locking plates fitted. The middle leading valve needed a special spanner making to tighten it. A couple of the plates needed some work to fit properly, one plate needed welding up and reshaping.

With the cylinder release valves and locking plates fitted the cosmetic covers to the outside cylinders were refitted after fitting insulation in to the cylinder covers.

Before refitting, the inside of the cosmetic covers were painted.

The leading bogie splashers have been refitted.

The cylinder drain cock linkage is now fitted with the remaining pins cross drilled and fitted with cotters.

The Cartazzi horn grinding is complete. The Cartazzi axlebox spring bearers and the axleboxes have been tried in and their fit is good. The axleboxes have now been removed and the bronze wedges fitted to their tops. The upper spring bearers have had their oilways thoroughly cleaned out ready for refitting.

The left Cartazzi bearing scraping has been resumed.

The left spring bearer steel wedges were re-machined to true up and remove wear. This removed some of the oil ways and these are being recut.

The ashpan sprinkler pipe has been fastened in place being connected to the ashpan water supply bulkhead fittings. Small brackets were made to stand the pipe off the ashpan and these have now been welded to the pipe and ashpan.

The rear grate support bar had a bit of rock in it and there was a danger that in traffic it could be shaken out of one of the end supports, so the centre support has been ground back and now the bar locates well. The trailing section of the grate has been put in.

Work continues on the washers and locking cotters for the loco brake table ends. All the cotters are made and the right side assembly is completed.

Painting of the inside of the cab has been completed. This has allowed the window runners to be refitted. The removable centre roof section has also been painted inside to top coat and is ready for refitting.

In the smokebox the last tacks to the right steel steam pipe have been applied. The middle and left being ready for welding as they have been for weeks now. We have been unable to progress the smokebox as we have been waiting for the welder to be available to come to York do the final pipe welding. With work still required on the pipes in situ we are unable to fit anything in the smokebox that will hinder access to the pipes. Though the piping team have managed to put in the atomised lubrication pipe to the middle cylinder.

The two stub pipes that come from the boiler front tubeplate in the smokebox are now ready to fit, once the steam pipes are removed. The atomiser/whistle supply has now been received from the welders, after they lost it so that was delayed a week! Both pipes have been hydraulically tested and the welded pipe has had independent testing of the weld.

Enough is enough so when I collected the stub pipe I told the welders they had lost the job for the steam pipes. Within a couple of weeks another welder was found and he was on site and has taken the left and middle pipes away for final welding and they will be refitted once we get to Crewe. The new welder is due at York again next week to finish and take the right pipe away.

In preparation for the arrival of the "new-new" welder, and as the geometry of the steam pipes is now fixed, the smokebox front plate was removed, which will stay off until the chimney casting is put in.

Special mention should be made of the hard work put in to this job by our volunteer who has produced three complex steel steam pipes. Feedback from our current welder on the quality of the work we have done was very positive.

The only thing the welder required us to do is to make a short piece of straight pipe to go in the superheater header flange on the right pipe to close up a root gap.

As work on the steam pipes is coming to an end the smokebox was cleaned out.

In preparation for the fitting of the blastpipe casting two thin ply covers have been made for the top of the saddle casting to prevent anything falling into the steam chest, while allowing the blastpipe to be bolted in place for the move to Crewe.

On the blastpipe casting the fabrication of the lower spark arrestor tray has been completed. This means the blastpipe casting is available for fitting.

In further preparation for front end reassembly and the refitting of the cod's mouth gear, the outer operating shaft supports were retrieved from store, cleaned and prime painted.

The middle piston being lowered in front of the smokebox during fitting. 29 June 2021
Photograph: Peter Brackstone

Middle piston being lowered

The right trailing Cartazzi hornstay is carefully ground to provide the correct clearance for the axlebox. 1 July 2021
Photograph: Richard Swales

Trailing Cartazzi hornstay

The right steel steam pipe is fabricated and tacked in situ. 1 July 2021
Photograph: Richard Swales

Right steel steam pipe

The brake ejector pipework is fitted, and there's still plenty of pipes to go. 3 July 2021
Photograph: Richard Swales

Brake ejector pipework

The middle piston and cylinder covers are fitted, as is the leading middle valve cover and right valve guide. 3 July 2021
Photograph: Richard Swales

Piston and cylinder covers

The completed conjugated gear assembly in front of the left cylinder 8 July 2021.
Photograph: Richard Swales

Conjugated gear assembly

The return crank and rod during assembly. 10 July 2021
Photograph: Richard Swales

Return crank and rod1

All the boiler cladding panels are now fitted. 15 July 2021
Photograph: Darrin Crone

Boiler cladding panels

The left return crank and rod fitted to the loco. 15 July 2021
Photograph: Richard Swales

Left return crank and rod

A new lower spark arrestor tray has been fabricated. 15 July 2021
Photograph: Richard Swales

Lower spark arrestor tray

The inside of the coal space is being painted. The strap added during conversion for A4 use can be seen. 17 July 2021
Photograph: Richard Swales

Inside of the coal space
Jan to Mar 2016 Apr to Jun 2016 Jul to Sep 2016 Oct to Dec 2016 Jan to Mar 2017
Apr to Jun 2017 Jul to Sep 2017 Oct to Dec 2017 Jan to Mar 2018 Apr to Jun 2018
Jul to Sep 2018 Oct to Dec 2018 Jan to Mar 2019 Apr to Jun 2019 Jul to Sep 2019
Oct to Dec 2019 Jan to Dec 2020 Jan to Jun 2021 From Jul 2021
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