| Table 9a. Estimated observation SDs. | |||
| Index | Fleet number | Age | Estimate |
| 1 | 1 | 1 | 0.61647 |
| 2 | 1 | 2 | 0.24063 |
| 3 | 1 | 3 | 0.06436 |
| 4 | 1 | 4 | 0.06436 |
| 5 | 1 | 5 | 0.06436 |
| 6 | 1 | 6 | 0.06436 |
| 7 | 2 | 1 | 0.47210 |
| 8 | 2 | 2 | 0.22732 |
| 9 | 2 | 3 | 0.22732 |
| 10 | 2 | 4 | 0.22732 |
| 11 | 2 | 5 | 0.22732 |
| 12 | 3 | 1 | 0.37210 |
| 13 | 3 | 2 | 0.25883 |
| 14 | 3 | 3 | 0.25883 |
| 15 | 3 | 4 | 0.25883 |