During the bogie overhaul for D1013, you may have noticed that each of the two intermediate gear boxes (one on each bogie) has a date for “float rectified” 11/74 and 4/75, which suggests that the last time D1013 received any major attention on the bogies was around mid-end September 1975.
Mike Woodhouse, who was a fitter at the time at Laira has confirmed to the WLA that D1013’s final overhaul was at Swindon Works in January 1972, which saw it leaving with bogies A85 and B73 (both Crewe built). In mid-1975 at Laira, Mike recalls that they were experiencing intermediate gearbox failures on examinations, where metal bearing debris was being picked up on the magnetic filters.
It was thought that D1013 suffered the same double-trouble and because there were new overhauled units available at Swindon Works Stores, two intermediate gearbox units were transported to Laira for D1013 in 1975. By this time, all double bogie changes had ceased, and none were overhauled after the early 1970’s; in fact, it was a scramble to get a bogie assembled for D1023 Western Fusilier, following the Oxford axle derailment failure. It was only the fact that Swindon Works had two intermediate gearboxes in stock that saved D1013 from being withdrawn from traffic.
Mike goes on to say that the senior management at Paddington CM&EE department were told to curb the finance spending on the Class 52’s, even a double bogie change with other members of the class was out the question, with staffing restraints, not to mention valuable time spent on the jacks.
With regard to the intermediate gear boxes themselves, these were originally water cooled which was a problem as the water hoses were prone to failing. It was eventually realised that water-cooling had over-engineered the problem and it was possible that Swindon Works had decided to use a different bearing with different “float” or at least had altered the float to prevent the gearbox failures, from around 1962/63. Once modified, the intermediate gearboxes would have a white line painted across the top and down the front and rear sides, along with added wording for the actual date modified eg “Float Rectified 9-75”.
The “float” refers to the lengthwise movement of a rotating shaft or bearing assembly along its axis to ensure that bearing isn’t too tight to cause excessive heat, wear and failure.
So now you know!