From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Measurement graphs showing axle tramping at various speeds for a continuous battery box support.
| Identifier | ExFiles\Box 164\4\ img003 | |
| Date | 12th January 1931 guessed | |
| 14.99 SHEET II CONTINUOUS BATTERY BOX SUPPORT MEASUREMENTS AS IN SHEET 1 14.99 M.P.H 18.45 M.P.H 25.83 M.P.H 30 M.P.H CRITICAL AXLE SPEED TRAMPING | ||