LOCOMOTIVE ENGINEER'S REPORTS
In April 2022 Sir Nigel Gresley returned from an overhaul which took more than six years and cost about £800,000 plus about £100,000 for the support coach. If you would like to make a donation towards the cost of this overhaul please click on the donate button.
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| Overhaul Reports 2015-2022 | Return to Home Page | |||
From January 2026.
16 January 2026
The manifold ejector valve has had the square on the spindle lengthened to allow a better fit of the handle. Looking at the dimensions it appears that some of the original square was threaded to add a nut, as originally the handles were pinned on. The square was cut in the plugged handle and the handle fitted to the spindle square. It's now a nice tight fit. The valve head was skimmed and taken back to Crewe. On the loco the valve head was lightly lapped in to the valve body, the seat in the valve initially lapped with our lapping jig. Finally the valve cap was lapped on the body and valve assembled with 2 new rings of packing on the spindle. With the valve complete the manifold isolation was opened.
The left piston crosshead was retrieved from the boilershop having been weld repaired. There was some minor cracking in the top end of the original drop link welds and the old weld was comprehensively ground out before re-welding to the crosshead casting.
The inside of the boiler casing hatches, painted white, were cleaned and it's a great improvement so I left them up for the next week. In the cab the M8 stand cover was also given a coat of paint.
In preparation for welding the cracked footplate angle behind the left loco buffer, the fairing screws were taken out and the fairing removed and hung on the buffer. The surrounding area was covered to keep grinding off the bogie, Gresley gear and leading left valve crosshead. Also to enable welding the electrical systems, AWS/TPWS, OTMR and GSMR were all disconnected. As we also change the batteries every year, the GSMR batteries were replaced but were not reconnected.
The new rubber for the tender vestibule was cut using the old sheet as a pattern. The holes in the old sheet were also copied. The steel retaining strips on the tender were removed and then the rubber fitted. The vestibule outer plate moves relative to the rest of the tender so some of the holes were drilled in situ as they didn't exactly match up. Some of the screws are in almost inaccessible corners but we managed to get it fitted and secured. It's a big improvement on the old perished sheet.
The lubrication exam continued with cleaning the right side buttons, then starting the left. The mops in the expansion link tops were also removed. They are open so get very dirty. They will be replaced.
By now the footplate angle welding was finished so the area was cleaned up and painting the weld area was started. We then put staging up the front of the loco so that the smokebox door knob could be welded.
The middle valve tailrod clack previously removed was refurbished. The clack valve was lightly lapped but looked OK and the cap lapped on to the body. The pipe connecting threads were cracked so these were silver soldered and the female cone lapped with a spare pipe cone to ensure a good fit on the pipe cone on the loco.
The front left fairing was refitted after painting the angle. We then removed the left side rods. The joint pin was in better condition than the right but did have similar marking so it was decided to grind the pin journal and renew the bush. The pin was lapped in to the rod and fits very well. The leading coupling rod bush whitemetal had some sections missing from its edge. I've seen this type of wear before and the bush wasn't complaining, but on reflection it was decided to re-metal the bush.
The speedo was due calibration so it was removed from the speedo crank.
The gauge glasses on our loco are slightly out of position. This hasn't been a problem but it was decided to make extended lower nuts to compensate for this. The threads on the gauge frames were accurately measured and a gauge made to these dimensions so that nuts could be made to the correct size. Due to time and wear they cannot be relied on to be a standard size. A ring gauge made to measurements taken was then taken to Crewe to be tried on the frames.
The tender and Cartazzi lubrication pads, underkeeps, bearings and journals were examined.
The left rod bearings and crank pins were measured and the results sent to the CME's office. The joint pin and bush were found out of spec so need attention, irrespective of surface wear. The pin journal was ground by LNWRh while we pulled the bearing out. The leading rod was then taken to the press to remove the left leading coupling rod bush.
The speedo was calibrated and remounted on the speedo crank.
The new main power supply batteries were fitted.
The right tender and Cartazzi axleboxes were examined and a start was made on draining the coupled axleboxes.
The left leading coupling rod was put up on the press and a plate made to fit across the bush. The bush was then pressed out and the key removed. The bush was then given to LNWRh for metalling.
With the left crosshead being prepared for refitting, the oilways in the lower surfaces were re-cut as they had worn very shallow.
The left little end pin and the area around the joint pin hole in the trailing rod was di-pen examined.
The outside little end nipples and pin trimmings were gauged. The right were refitted and the oil box cap tightened and the box filled with oil.
The axles were ultrasonically tested.
The tender shovel plate was removed, and then the tender floor. This was to access the tender front which is showing corrosion. The needle gun was connected to an air supply and the tender descaled. Meanwhile the shovel plate was cleaned off for painting.
The middle little end oil box was removed and was cleaned out and the nipple and pin trimming gauged.
The middle piston packings were then taken out as they required re-gapping. After re-gapping it was decided to surface grind the packings. Something we haven't done before and as they are not magnetic we will have to make a jig to hold them. A ring was made to locate their bores.
Measuring of the left rods and bearings continued with connecting rod bearings, driving crankpin and gudgeon pin. The left big end lubricating felt took some getting out of the rod. On the right most of the pads could be pushed out with a thick wire down the oil way, but the left seem to be smaller.
The smokebox door was painted with high temperature paint.
The bogie axlebox oil trays were removed. The pads, journals and axleboxes look examined.
The left crosshead saw its last prep for refitting with cleaning through the oilways and scotch-brighting the piston rod taper. The safety cotter hole in the crosshead cotter was lengthened a little just in case the crosshead cotter went in a little further than when it came out. The crosshead was then put in the slide bars and the outer lower slidebar refitted. The bolts were then fitted and flogged up. The crosshead was then pushed on to the piston rod and finally the cotter driven in and we got a good fit on the safety cotter.
The left droplink button cap was refitted but it was decided to make up a new trimming. The nipple, pin trimming and cover were refitted to the little end oil box.
With the needle gunning finished on the tender front, it was sealed against the cab floor and painted to grey undercoat, while the shovel plate was painted to black gloss.
The GSMR enclosure door seals against a foam seal which was displaced and in some places loose. The seal was resecured.
The left connecting rod little end was di-pen examined.
The speedo wheel compensator enclosure was security wired, meanwhile the security wire was removed from the axlebox lubricator so the plugs can be removed for draining.
The threads for the new gauge frame nuts were cut in the ends of a piece of bronze. They were then tried on the frames before further machining.
The final gloss coats were put on the tender front and shovel plate. The left crosshead was painted to undercoat.
The cylinder lubricator had been with the CME to solve the slow leak from the bottom. It was found that the lubricator mounting flange is a separate piece that is screwed with hidden screws to the lower boss on the lubricator body. It looked like that is where the leak was coming from. So, some new screws were made and the plate refitted. The lubricator was then returned to Crewe and fitted. Next time we should use a crane. The lubricator mounting bolts were fitted and split pinned. The oil pipes were then refitted being careful to follow the tag numbers and locations. A special spanner was made up as the pipe nuts are very difficult to get to. As they are, some were a little damaged so had to be filed to get the spanner on them. The nuts were carefully cleaned out and finally blown out with compressed air.
The refitted front left buffer fairing received some filling and was then painted by LNWRh.
The coupled wheel pad and journal exam was began with the left leading.
With the cylinder lubricator piped up, a few inches of oil was put in and left overnight to see if we still had a leak. All was dry next day so the pipes were primed to the atomisers. This was a long process as we primed one pump at a time with an individual atomiser way test point open. All primed in sequence as our schematic. The lubricator drive rods and gear were then refitted.
The left leading coupling rod bush was finished machined. Sharp edges to the bronze were then taken off and a chamfer added to the outer edge of the whitemetal in the hope that this will make it less likely that the edge will break. With the bush out of the rod a new felt pad was cut. The bush was then returned to the press and was pressed back in to the rod. As expected, with less interference the bush pressed in with a lower force but decent enough for further use. In the rod the bore was checked for closing up and was within tolerance.
With all the new left rod felts cut they were put in oil to soak.
Back at the loco the last coat of black gloss was put on the left crosshead.
One of the in service gauge glass protectors has a weak spring that is supposed to hold the rear cover closed. The protector spring was taken off and the spring re-heat treated and refitted. The new lower gauge frame nuts were finish machined.
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| Jan to Jun 2025 | Jul to Dec 2025 | From Jan 2026 | ||
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