81012 1A83 0813 Northampton – Euston 11vb 250485
| Milepost/Station | Sched arr/dep | Actual arr/dep | Passing time | variance | Av speed |
| 40.21 – Leighton Buzzard | 0846 dep | 0848.30 dep | +2.5 | ———- | |
| 40 | 0849.28 | 13.03 | |||
| 39 | 0850.47 | 45.56 | |||
| 38 | 0851.50 | 57.14 | |||
| 37 | 0852.44 | 66.66 | |||
| 36 – Cheddington | 0853.33 | 73.46 | |||
| 35 | 0854.23 | 72 | |||
| 34 | 0855.12 | 73.46 | |||
| 33 | 0856.02 | 72 | |||
| 32 | 0857.21 | 45.56 | |||
| 31 – Tring | 0859.44 | 25.17(us-uf) | |||
| 30 | 0900.46 | 50 | |||
| 29.25 | 0901.23 | 72.97 | |||
| 28 – Berkhampsted | 0902.16 | 84.9 | |||
| 27 | 0902.56 | 90 | |||
| 26 | 0903.36 | 90 | |||
| 25 | 0904.16 | 90 | |||
| 24 – Hemel Hempstead | 0904.54 | 94.7 | |||
| 23 – Apsley | 0905.32 | 94.7 | |||
| 22 | 0906.08 | 100 | |||
| 21 – Kings Langley | 0906.45 | 97.29 | |||
| 20 | 0907.21 | 100 | |||
| 19.5 | 0907.39 | 100 | |||
| 18 | 0908.35 | 96.42 | |||
| 17 – Watford Jn | 0909.12 | 97.29 | |||
| 16 – Bushey | 0909.48 | 97.29 | |||
| 15 | 0910.27 | 92.3 | |||
| 14 | 0911.06 | 92.3 | |||
| 13 | 0911.44 | 94.7 | |||
| 12 | 0912.22 | 94.7 | |||
| 11 – Harrow | 0913.00 | 94.7 | |||
| 9.75 | 0913.47 | 95.74 | |||
| 9 | 0914.14 | 100 | |||
| 8 – Wembley C | 0914.50 | 100 | |||
| 7 | 0915.26 | 100 | |||
| 6 | 0916.04 | 94.73 | |||
| 5 | 0916.43 | 92.3 | |||
| 4 | 0917.26 | 83.72 | |||
| 3 | 0918.12 | 78.26 | |||
| 1.5 | 0920.08 | 46.55 | |||
| 1 | 0920.56 | 36 | |||
| 0 – Euston | 0923 arr | 0923.32 arr | 0 | 23.07 |