Having considered the options for the refurbishment of the coupled wheel axleboxes it was decided that the existing bearings and horn liner bronzes were beyond recovery and should be replaced. The unwanted 12mm holes will be plugged and sealed and the 3/8” BSW holes refurbished to allow the new liners to be fitted as originally intended.
This proposal was put to the WSRA Board for approval of the additional costs expected to be involved before placing orders for the supply of new bronze bearing castings and the liner plate materials.
Meantime the 4 crosshead slidebars have been refurbished and polished before being fitted in their respective positions on the support brackets (or ‘G’ irons) behind each cylinder. This enabled their alignment to be checked as parallel to the cylinder centre datum wires; and to ensure they are correctly spaced to determine the thicknesses of bronze packing pads to be fitted both at each ‘G’ iron and at each rear cylinder cover before being finally bolted in position.
Shown are the two RH slidebars in position parallel to the datum wire. It is just possible to see the gap between the lower bar and the cylinder cover for which a packing pad is needed. It is also just possible to see the end of the top bar has been stamped ‘5553’ which is the locomotive no. on which this bar was first fitted by the GWR
This is another view of the RH side showing how the slide bars are supported by the ‘G’ irons to which they are bolted by the bolts recessed into each bar. The outer end of the lower bar top surface has a sloping flat machined into it to provide an adequate running clearance from the connecting rod when fitted. This is not required for the upper bar owing to the cylinder centre line being 2 ½” above the driving axle centre line.
This photo shows the LH slide bars have also been fitted. Again it is possible to see the gaps between the front of each slide bar and the rear cylinder cover lugs waiting for their respective packing plates.
First published on the WSRA 4561 restoration blog.