This nice shot of " Merchant Navy " 35020 , " Bibby Line " at Waterloo reminds us that it was this member of the class that brought about the dramatic and major rebuilding of the whole class when in May of 1953 this engine suffered a fractured main axle whilst working through Crewkerne .
With that axle taking the drive from the inside cylinder in addition to having the chain for the valve gear mounted on it a subsequent examination showed a weakness in the axle of not only 35020 but with similar problems apparent on half the other " Mechant Navy " locomotives so examined .
As a direct result , therefore , the whole class were rebuilt from their earlier distinctive " air smoothed " design to that seen here , now fitted with outside Walschaerts valve gear but retaining their original frames , boiler and wheels.