Professional consultancy correspondence of Ken Johnson Correspondence files files by name of subject. Alcan W S Atkins (Trowse Bridge) British Leyland Bath Power Transmission British Rail BHP Broken Hill Proprietary BTG British Technology Group Cegelec Corinth Tramway Cranfield Precision Traction Drive Davy Mackee (Poole) - rolling foil ERS Tech Pos-grip Ford - Perbury Report GKN Hydratight - Pipe Coupling National Centre of Tribology - Risley NRC Tribology Lab - Vancouver Pandrol - Rail profile measurements Perbury Engineering Ltd Philips Consulting - visit to Holland Plint Ricardo Schlumberger Shell Thornton SKF Residual stress assessment SKF Fatigue SKF Holland SKF Luton SKF Contact stress investigation Skalzo Enginers - K H Hunt; Wilson, Ehrig & Associates 1980-1990s