B12/3 Assesment Update
The work has been progressing to dismantle and examine the critical items identified in our assessment schedule.
All six driving and coupled axle box leaf springs have now been removed, and it has been found that the leaf spring to the leading driving axle on the left hand side has a broken top leaf. This indicates and confirm that the leaf springs have been stressed as a consequence of the impact. All six driving and coupled axle box springs, along with the two bogie equaliser beam leaf springs are on pallets ready for despatch to a specialist spring company for full examination and testing.
It has been found that the tender tank has been shifted forward by about 1/4" by the impact, and an internal examination has found a number of bracing bars to have fractured due to the surge of water. This has also caused the connection points to the sides of the tender to be flexed resulting in filler to break away and the steel to have pin holed. These will require weld repairs which then has a knock on effect of damaging the paint and lettering. These are going need to be re-plaited and the lettering renewed to restore to original pristine condition.
The bogie has been fully dismantled, and work started on the overhaul of the wheels with the first axle in the wheel lathe for tyre turning.
The lateral slide bronze plates have worn badly and are life expired requiring replacement, along with some remedial work to restore wear on the swivel bearing plates on the underside of the bogie pivot stretcher which fastens beneath the cylinder block in the engine frames.
The retaining pivot pin bolt has been deformed by the incident at Holt and needs replacing.
One of the bogie frames has developed a crack in the corner of the horn guide slot, which is attributable to the impact damage and will need to be ground out and weld repaired.
The winter overhaul work can then continue with the axle boxes being fully re-metalled.
The engine to tender draw links and pins have been mag-particle NDT examined, and there are no immediate signs of damage to these parts.
Regards the maintenance work to the motion, this has progressed well with the relevant valve gear components dismantled, and the expansion links despatched to a specialist Company in the centre of Birmingham for annealing, the slots dress grinding out, followed by them being re-case hardened and the curved slots final fine grinding to the required dimension. New hardened steel die blocks then being manufactured to suit the new slot widths, machined to the required clearance of between 0.003" to 0005".
Given the amount of work that has been identified due largely to the crash damage, along with the winter maintenance work, it is doubtful she will be back before the March Gala.