Sir Nigel Gresley overhaul – update 8

In The Works, the overhaul of Sir Nigel Gresley continues. Locomotive Engineer Darrin Crone provides us with an insight of the previous couple of weeks’ work.

This is the eighth update – you can catch up on the previous posts here.


As mentioned in a previous report there’s still plenty of meat in the dragbox but the nuts look a little tired after being covered up in the dark for so long. We were very pleased to find that when the first nut was removed the thread on the bolt looked to be in good condition, and when a die nut had been run down it to clean it up it looked like new. This means that the fitted bolt, still tight in its hole, can be reused with the addition of a new nut. However, three of the bolts had to be removed as the treads showed signs of corrosion. And, as usual with steam locomotives, the three requiring renewal were the most inaccessable.


Heating the dragbox nuts to help get them off the bolts.


We first attempted to remove them by heating them then allowing them to cool. But they didn’t respond to this so we then drilled down the centres and burnt out as much material as safely possible to avoid any damage to the dragbox casting. By removing material – and with the use of a big hammer – we eventually got them out. There was certainly no danger of the dragbox coming out in traffic if these bolts were anything to go by.


The old nuts and washers on the upper dragbox fitted bolts are removed and temporary nuts put on those bolts that are to be left in place.


At the front of the locomotive the front coupling hook was removed for inspection and cleaning-out of the piston ring grooves was completed. The dye penetrant testing of the spring hanger brackets was continued this week.


The leading right hand combined spring and brakeshaft bracket upside down on the end of the marking out table for measuring prior to repair.


Painting of the the sandboxes and suspension components continued this week, with the first coats of undercoat being applied. We now have green, white and grey painted parts. It’s confusing to me, but the Painting Team know exactly where they are up to.


The sandboxes looking resplendent in undercoat.


The combined spring and brake shaft brackets have now been measured and compared to drawing. The removed right hand bracket was lifted onto the marking out table so that we could measure it accurately. As this bracket is to be repaired it will be modified to match the left bracket that is still on the loco.

The decarboning of the exhaust passages continued this week. On Friday the Engineering Team were still pulling out lumps so there’s still work to do in here.

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