Date | Section of line | Broad | Mixed |
| 1 Jan 1862 | Total mileage | 790m 8c | 314m 18c |
| 8 Jan 1862 | Mwyndy & Brofiskin and Gellyrhaidd branches | 4m 7c | |
| 1 Feb 1862 | Exeter - Cowley Bridge junction (mixed)1 | 1m 27c - | 1m 27c |
| 1 Mar 1862 | Shepton Mallet - Wells2 | 4m 62c | |
| ? Mar 1862 | Slough - Winsdor (mixed) | 3m 5c - | 3m 5c |
| ? Mar 1862 | Reading (junctions mixed) | 0m 59c - | 0m 59c |
| 31 Mar 1862 | Norton Fitzwarren - Watchet1 | 14m 48c | |
| 1 Jul 1862 | Swansea Harbour Railway4 | 0m 60c | |
| 1 Aug 1862 | High Wycombe - Thame | 13m 72c | |
| 11 Nov 1862 | Hungerford - Devizes | 24m 32c | |
| ? Mar 1863 | Tonmawr - Glyncorrwg9 | 6m 35c | |
| 2 Mar 1863 | West London Railway junctions | 6m 15c | |
| 1 Jun 1863 | Didcot station junctions(mixed) | 1m 12c - | 1m 12c |
| 15 Jul 1863 | Swansea Harbour Railway (mixed)4 | 0m 60c - | 0m 60c |
| 24 Aug 1863 | Truro - Falmouth10 | 11m 68c | |
| 7 Sep 1863 | Johnston - Milford | 4m 0c | |
| 8 Sep 1863 | Bristol - New Pier Passage | 11m 37c | |
| 1 Oct 1863 | Princes Risborough - Aylesbury | 7m 27c | |
| 29 Oct 1863 | Chippenham - Calne | 5m 24c | |
| 1 Jan 1864 | Portskewett - Pier | 0m 74c | |
| 28 Mar 1864 | Conwil - Pencader8 | 8m 10c | |
| 14 Apr 1864 | Savernake - Marlborough | 5m 49c | |
| 18 Apr 1864 | Neath - Middle Duffryn (mixed)4 | 21m 41c - | 21m 41c |
| 18 Apr 1864 | Gellt Tarw Jctn - Merthyr (mixed)4 | 6m 23c - | 6m 23c |
| 18 Apr 1864 | Dare & Amman branches (mixed)4 | 6m 77c - | 6m 77c |
| 1 Jun 1864 | Uffington - Faringdon | 3m 49c | |
| 3 Jun 1864 | Pencader - Llandyssil8 | 3m 42c | |
| 13 Jun 1864 | Yeovil Clifton Maybank branch | 0m 36c | |
| 13 Jun 1864 | Westbourne Park - Hammersmith3 | 2m 38c | |
| 1 July 1864 | Latimer Rd Jctn - Uxbridge Jctn3 | 0m 39c | |
| 16 Aug 1864 | Churston - Kingswear6 | 3m 63c | |
| 24 Oct 1864 | Thame - Oxford | 12m 75c | |
| 1 Nov 1864 | Myrtle Hill Jctn - Abergwili Jctn (mixed)8 | 1m 75c - | 1m 75c |
| 5 Dec 1864 | Llantrissant - Maesaraul Junction (mixed) | 3m 28c - | 3m 28c |
| 1 Jul 1865 | Tavistock - Launceston6 | 18m 76c | |
| 1 Aug 1865 | Tondu - Porthcawl (mixed)7 | 9m 58c - | 9m 58c |
| 16 Oct 1865 | Gellyrhaidd - Gilfach Goch | 2m 36c | |
| 16 Oct 1865 | Weymouth - Portland5 | 5m 37c | |
| 4 Jul 1866 | Newton - Moretonhampstead6 | 12m 13c | |
| 16 Jul 1866 | Hereford - Rotherwas Junction (mixed) | 1m 15c - | 1m 15c |
| 1 Aug 1866 | Tondu - Duffryn Llynvi (mixed)7 | 7m 7c - | 7m 7c |
| 11 Sep 1866 | Creech Junction - Chard1 | 12m 61c | |
| 1 Nov 1866 | Abergwili Jctn - Pencader(mixed)8 | 13m 54c - | 13m 54c |
| ? Nov 1866 | Chelsea Basin jctn - Longhedge (to standard gauge) | 1m 69c - | |
| ? Nov 1866 | Truro - Penzanze (broad gauge rail added)11 | 25m 69c | |
| 31 Dec 1866 | Total mileage | 905m 43c | 330m 48c |
| Metric conversion: 80 chains = 1 mile; 5 miles = 8 kilometres | |||
| Note 1: | Bristol & Exeter Railway | ||
| Note 2: | East Somerset Railway | ||
| Note 3: | Hammersmith & City Railway | ||
| Note 4: | Vale of Neath Railway | ||
| Note 5: | Weymouth & Portland Railway (joint GWR & London & South Western Railway) | ||
| Note 6: | South Devon Railway | ||
| Note 7: | Llynvi & Ogmore Railway | ||
| Note 8: | Carmarthen & Cardigan Railway | ||
| Note 9: | South Wales Mineral Railway | ||
| Note 10: | Cornwall Railway | ||
| Note 11: | West Cornwall Railway (opened as a standard gauge railway 1852.) | ||
Locomotive Class | No. (+/-) | Total | |
| 1 Jan 1862 | Total locomotives | 424 | |
| Star 2-2-2 | - 3 | 9 | |
| Fire Fly 2-2-2 | -19 | 43 | |
| Sun 2-2-2 | - 4 | 17 | |
| Leo 2-4-0 | - 4 | 14 | |
| Hercules 0-6-0 | 4 | ||
| Great Western 4-2-2 | 1 | ||
| Prince 2-2-2 | 6 | ||
| Iron Duke 4-2-2 | 29 | ||
| Avalanche 0-6-0T | - 1 | 0 | |
| Premier 0-6-0 | - 1 | 11 | |
| Pyracmon 0-6-0 | 6 | ||
| Bacchus 0-6-0 | 1 | ||
| Bogie 4-4-0T | 15 | ||
| Waverley 4-4-0 | 10 | ||
| Victoria 2-4-0 | +10 | 18 | |
| Ceasar 0-6-0 | 8 | ||
| Banking 0-6-0T | 4 | ||
| Standard Goods 0-6-0 | +12 | 102 | |
| Metropolitan 2-4-0T | +22 | 22 | |
| Hawthorn 2-4-0 | +26 | 26 | |
| Swindon 0-6-0 | +14 | 14 | |
| Sir Watkin 0-6-0T | + 6 | 6 | |
| B&ER 4-2-2 | - 1 | 19 | |
| B&ER 0-6-0 | 18 | ||
| B&ER 4-2-4T | + 2 | 6 | |
| B&ER 4-4-0T | + 4 | 10 | |
| B&ER 2-2-2T | 7 | ||
| B&ER 0-6-0T | + 1 | 1 | |
| VofNR 4-4-0T | 9 | ||
| VofNR 0-6-0T | 10 | ||
| SDR 4-4-0T | +11 | 35 | |
| SDR 0-6-0T | + 8 | 16 | |
| CCR 4-4-0T | + 2 | 4 | |
| Unclassified engines | 8 | ||
| 31 Dec 1866 | Total locomotives | 509 | |
| Key: | B&ER - Bristol & Exeter Railway VofNR - Vale of Neath Railway (merged with GWR Dec 1866) SDR - South Devon Railway CCR - Carmathen & Cardigan Railway | ||