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).
Electrical experimental record sheet logging mileage and component status.
| Identifier | ExFiles\Box 64\4\ scan0273 | |
| Date | 14th May 1929 | |
| ELECTRICAL EXPERIMENTAL RECORD SHEETS. Date on. | Location. | Date off. | REMARKS. | Miles reading start. | Miles reading finish. | Miles covered. | Total miles. 6-2-28 | 9EX | (contd) | | | 3660 | 618 | 17,624 5-3-28 | " | | | | 4356 | 696 | 18,320 12-4-28 | " | | | | 6093 | 1737 | 20,057 7-5-28 | " | | | | 7264 | 1171 | 21,228 7-6-28 | " | | | | 8679 | 1415 | 22,643 4-7-28 | " | | | | 561 | 1882 | 24,525 29-8-28 | " | Taken off chassis, examined found to be quite OK and replaced. | | 1970 | 1409 | 25,934 31-12-28 | " | | | | 8062 | 6092 | 32,026 18-3-29 | " | This switch is now obsolete being superseded by mechanical interlock switch. | | 8614 | 552 | 32,578 14-5-29 | " | | | | 9926 | 1312 | 33,890 | ||