The Sir Nigel Gresley Locomotive Trust LtdSubscribe to 60007

Registered Charity Nº1079591

OVERHAUL 2015 - 2018

All the overhaul photos may be found here.

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

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Notes from information supplied by Darrin Crone, Locomotive Engineer.

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From October 2017.

16 October 2017

The old bushes have now been removed from the leading vacuum cylinder outside bearings but we are still waiting for delivery of material to make up the new bushes. Both leading vacuum brake cylinders have now been reassembled and checked for piston movement. Both are satisfactory and now only require painting. They have now been spot primed.

The large trailing loco vacuum brake cylinder is now being prepared for reassembly. Inspection of the cylinder shows that the piston ring has been rubbing and not rolling correctly over a small part of its length. We have concluded that this is caused by wear in the bush that guides the piston rod, which has allowed the piston to tilt slightly in the cylinder. Spare bushes are available from spare parts suppliers, but we are yet to confirm the exact size of bush we need, as our 24" cylinder is unusual (apparently) in having a 1-1/2" diameter piston rod.

Progress has been made as the new piston ring has been trial fitted to the 24" piston, and it has been put in the cylinder and inspected for movement. It seems fine with the ring rolling satisfactorily when the piston operates square to the bore.

The steam heat pipework has now been thoroughly cleaned off. The pipework has been inspected and is in very good condition over the front bufferbeam to Cartazzi section. It was then painted in high temperature paint. The first section of pipe under the front bufferbeam was fitted with the air brake pipework in this area, complete with leading air brake valves. This required the removal of the centre section of streamlining behind the front coupling hook.

By the end of the week the steam heat pipework was refitted back to the Cartazzi. It still requires some final fitting to secure it and there is a joint which will have to be remade. Along the same side of the frames runs the steam chest pipe and this was trial fitted this week. To give us a fixed starting point the outside steam pipe from which it runs was temporarily refitted.

Before fitting, the steam chest pipe needed a lot of cleaning as it had a thick layer of carbon adhering to it. The Engineering Team volunteers spending a lot of time doing this while avoiding damaging the soft copper underneath.

All the valve ring pegs have been removed from the valve heads and the threaded holes carefully cleaned up. After final inspection they will be machined to fit the new valve liners.

In front of the smokebox, brackets run along the frames to supports a foot plate between the frames. When the loco was dismantled the bracket on the left side was loose and there was evidence that the bracket had been loose and re-tightened repeatedly in the past. When the bracket bolts were removed it was found that the bolt holes were damaged and there was very little clamping area for the bolt head. The holes were repaired this week and new bolts were fitted.

At the other end of the frames work has resumed around the Cartazzi inner frames with cleaning and needle gunning preparing this area for testing and painting.

Work on the wheels continued this week with primer being applied and our first efforts at filling the surface imperfections in the castings. The filler went on OK and some test sanding was done. This will be continued next week.

After taking measurements last week the axleboxes are now having bearing material cast on at the workshops of the NYMR at Grosmont.

The handbrake screw from the tender has been condemned as beyond economic repair. To produce a new one we need a suitable drawing. Measurements have been taken so that we can produce a drawing. The drawing we have in our records is different form the screw we have so we visited the NRM archive to look at the drawings they have, and again we could not find a drawing that shows the handbrake screw we have.

The air brake piping has been refitted around the front bufferbeam. 14 October 2017
Photograph: Darrin Crone.

Air brake piping refitted

The steam heat pipework was refitted to the loco this week. This view shows behind the front bufferbeam. The pipework for the steam heat still requires securing to all its brackets. 14 October 2017
Photograph: Darrin Crone.

Steam heat pipework refitted

The platework around the Cartazzi has been given another coat of cleaning and descaling in preparation for final testing as repairs to the inner frames are completed in this area. 14 October 2017
Photograph: Darrin Crone.

Platework around the Cartazzi

The overhaul of the leading vacuum brake cylinders has been completed with only painting now to be completed. 14 October 2017
Photograph: Darrin Crone.

Vacuum brake cylinders

A view from the end of the steam heat pipe at the cab end of the loco frames. The end of pipe can be seen on the right as it snakes up the frames. 14 October 2017
Photograph: Darrin Crone.

The steam heat pipe

The wheelsets continue to be finally cleaned and receiving coats of primer. The photo shows the progress so far with one of the bogie wheelsets. 14 October 2017
Photograph:Darrin Crone .

The wheelsets cleaned

The piston valve heads have ow had all the pegs removed and are ready for machining to suit the new valve liners. 14 October 2017
Photograph: Darrin Crone.

The piston valve heads

9 October 2017

The valve heads were removed from their spindles last week for machining to suit the new valve liners. Before machining can begin the ring pegs require removal. These pegs project in to the ring grooves to stop the piston valve rings from rotating around the valve head. They are screwed in to the valve head then machined flush with the valve head. A preliminary attempt was made to see if the pegs would unscrew, but unsurprisingly they would not so we proceeded to drill them out. This was done using the NRM's Richmond radial arm drill. By the end of the week they had all been drilled out but the threaded holes still require clearing of the remains of the peg threads.

The last of the coupled spring holes were ground out this week. This will assist in the free movement of the spring hanger bolts in traffic as they should not now foul the springs.

The wheelsets returned from re-tyring are now looking very good, as remarked by a number of observers last week. The tyre edges, balance weights and axle ends are now prime painted and we are now trialing filling some of the spokes on one of the coupled wheels. We know other locos have had their spokes filled before painting and it does help in cleaning when the loco is back in traffic, as well as looking really good.

The lubrication connections to the bogie go through the loco bogie stretcher via screwed in fittings. The stretcher collects water and this water can find its way on to the bogie bearing surfaces via these connections if they are not a good fit in the stretcher. To ensure a good fit the top of the stretcher where the fittings seal has this week been spot faced. When the fittings are replaced they will be sealed with copper washers against the stretcher.

This week NYMR technicians visited us at York to measure the journals of the bogie and coupled wheels so that the finished dimensions of the axleboxes can be determined.

The tender sump was found to be holed when it was removed from the tender tank. This week the bottom plate was cut out and the bottom flange at the centre of the plate recovered. New plate is now on order. We also had a look over the ashpan. It is in a generally sound condition though the side plates are warped near the damper door. Before work can begin we will have to move it to a suitable location from where it is at the moment in the north yard.

As riveting around the leading vacuum cylinder stretcher is now complete the air brake pipe runs in this area can be installed. This was progressed this week, meanwhile work continues on cleaning the pipework retrieved from store. The bolting for the flanges on the steel pipework for vacuum and steam heat have been removed and are being cleaned and die-nutted.

The reverser shaft was fitted last week. This week the pins for the spiral spring and vacuum clutch, both of which are fitted to the shaft, were refitted greased and finally pinned in place. The lifting arms that go on the end of the shaft were retrieved from store and cleaned.

The repaired leading vacuum cylinder centre bearing was returned to York this week. It was put in place and aligned with the outside bearings using a 2" diameter pipe. This is the same diameter as the trunnions on the brake cylinders. When in place the mounting holes for the centre bearing were marked and it was then removed for drilling. After drilling it was refitted and its alignment re-checked, and is very good. The bearings have now been removed. The centre will be painted and the outside bearings will have their bushes renewed.

The brake cylinders are now being reassembled with the first, one of the leading 21" cylinders, completed by closely following the official BR instructions. A test of the piston under gravity showed that it moves satisfactorily.

The staying of the new side plates of the boiler at Llangollen is now complete. This view shows the inside of the firebox. The area of new staying is apparent. The bottom row of stays will be put in after the replacement of the foundation ring. 4 October 2017
Photograph: Paul Aston.

Boiler side plates

Steady progress is being made with the wheelsets. They have now been thoroughly cleaned of the grease and wax put on them to protect them during their repairs and primer is now being applied. 5 October 2017
Photograph: Peter Brackstone.


The pegs that prevent the rotation of the rings in the valve heads have been drilled out this week. This has to be done very carefully and requires accurate setting up to ensure no damage to the valve head as they are to be reused. 5 October 2017
Photograph: Darrin Crone.

Drilling a ring peg

One of the valve ring pegs after drilling out on 5 October 2017.
Photograph: Darrin Crone.

Drilled out ring peg

Much time and effort has been put in to cleaning and preparing pipework for refitting. This pipe is part of the run from the steam chest to the cab. It originally controlled the exhaust steam injector but is now used for the steam chest pressure gauge. 5 October 2017
Photograph: Darrin Crone.

Cleaning pipework

The leading vacuum cylinder centre bearing bracket was put in its correct position this week and the mounting holes drilled to suit. It was then removed for painting. Here it is on the painting bench. 5 October 2017
Photograph: Darrin Crone.

Vac cylinder bearing bracket

The bottom of the tender sump was cut out this week and the flange in the plate recovered. The flange can be seen inside. New plate will be welded in and the old flange re-used. 5 October 2017
Photograph: Darrin Crone.

Bottom of the tender sump

The completed vacuum cylinder has been assembled using new seals and the piston checked to ensure free movement. Andy Barwick appears pleased with the results of his efforts. 6 October 2017
Photograph: Malc Bateman.

Completed vacuum cylinder

2 October 2017

The new boiler side sheets should now be fully stayed with the last 20 stays planned for fitting this week. With this complete, plans are now being made to turn the boiler onto its side so that the combustion chamber copper welding can be continued up the sides and eventually across the roof plate.

A great deal of effort has been put into getting the wheels in a suitable condition for painting, with most of the volunteer Engineering Team members putting in the elbow grease. By the end of the week they were approaching the condition in which they left York. Paint was finally applied on Thursday to tyre edges after our painter declared them clean and rust free enough.

Further preparations for the tender tank lift were made this week with the gangway bellows being removed. The bellows are between the tender vestibule and the large plate that buffers against the coach connection. The plate is thick steel and is very heavy so had to be removed after some careful planning. It was lowered on to the buffer stops behind the tender and was later put to the side and tied up. The strips that hold the cover sheet were removed so that the damaged cover sheet removed could be removed.

The last water pipe fouling the lift couldn't be removed with a wrench as it collapsed when this was tried, so it was burnt off. After a last look round the tender we couldn't see anything else that could prevent the lifting of the tank, so packing towers were put in the corners and the tank was jacked. It was jacked a couple of inches and packed against the tender frames.

The last of the new spring hanger bolts were delivered this week and were checked against drawing by our placement student, who will be with us until summer next year gaining engineering experience as part of his university course. He also measured the hornstay bolts and holes on the bogie frames and is preparing a drawing of the bolts so new ones can be manufactured. The last bogie side control bolt cotter was put in this week, after a new washer was made, to give the cotter a good fit on top of the nut.

The vacuum brake and steam heat pipes were retrieved from store this week. A start has now been made on cleaning and assessing their condition prior to refurbishment and refitting.

The air brake components and electrical equipment removed from the coach returned to York this week after contractor overhaul.

The leading vacuum cylinder centre bearing was taken for weld repair and machining this week. The repair is now completed and it will be back at York next week for final positioning.

The failed clackbox castings have now been returned to the foundry. Our clackbox valves were taken to the machine shop that will be machining the castings. They have requested these parts to ensure they will be a good fit in the clackbox bodies and that the different sections of the complete clackbox can be separately pressure tested.

The reversing shaft has now been put back on the loco. As mentioned in previous reports the shaft has to have the spiral spring fitted as the shaft is passed through the frames. As the spring is a tight fit a sleeve was made to prevent damage to the shaft. The reverser clutch sheaves were also fitted to the shaft.

The piston valve heads from the middle and right hand valves require machining to suit the new valve liners. These can be very difficult to remove and it was important that they were not damaged during removal as we want to reuse them. They have now been successfully removed.

The valves and clack cap for the left hand clackbox were taken to the machine shop where the clackbox bodies will be machined. The clackboxes need these parts fitting for final pressure testing. 28 September 2017
Photograph: Darrin Crone.

Valves & cap for L/H clackbox

The tender tank is now lifted from the frames and stands off the frames on a couple of inches of packing. The gangway bellow assembly lays on its side ties to the buffer stops in the NRM workshop. 28 September 2017
Photograph: Darrin Crone.

Tender tank lifted from frames

The refurbished coach air brake cylinders were returned to York this week. 28 September 2017
Photograph: Darrin Crone.

Refurbished air brake cylinders

Packing can be seen below the tank in this photo of the rear bufferbeam area. The square section bars with bolts in their ends support the gangway connection and are spring loaded to push the connection out. 28 September 2017
Photograph: Darrin Crone.

Packing below the tank

Just part of the pipework being worked on at the moment. This is a collection of loco vacuum brake and steam heat pipework. 28 September 2017
Photograph: Darrin Crone.

Part of pipework being worked on

The first paint is being applied to the returned wheelsets. This is the driving set. 28 September 2017
Photograph: Darrin Crone.

First paint on returned wheelsets

Not mentioned in the report, we visited the works of K D Flavell who are refurbishing the superheater header. Here it is stood on the flange that fastens on to the boiler. The top and end faces are complete and this visit was to agree the repair procedure of the element holes.
Photograph: Darrin Crone. 29 September 2017

Refurbished superheater header

The reversing shaft was fitted this week. The spiral spring that counteracts the wight of the reversing assembly, and the vacuum clutch that locks the shaft in position can be seen. 29 September 2017
Photograph: Andy Barwick.

The reversing shaft

The leading vacuum cylinder centre bearing has had its fixing holes welded up as it is to be repositioned on the loco and new holes will be drilled through. The bottom of the "U" has been built up with weld and bored out to a specified diameter to suit the vacuum cylinder trunions. 1 October 2017
Photograph: Darrin Crone.

Vacuum cylinder centre bearing
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