Horizontal curvature for ELR BTC is based on the digitised notional centre-line, calculated in 100 metre sections. The average radius computation is weighted, however this should be treated as indicative only. The computed minimum and maximum radii are shown for completeness, and often report a much tighter radius than the physical railway. Radii calculations are influenced by the digitisation quality, and often produce inaccurate values at the extremities of the ELR, areas of tracks divergence, and locations of very tight curvature.
| Mileage | Schematic | Average Radius | Radius Range | Features |
|---|---|---|---|---|
| 7M 0286y - 7M 0330y | ⚪-⚪⚪⚪-⚪ | Straight | Blackheath Jn | |
| 7M 0330y - 7M 0440y | 🟠-🟠🟠🟠-🟠 | Moderately Tight (542 m) | 444 m → 646 m | |
| 7M 0440y - 7M 0550y | 🟠-🟠🟠🟠-🟠 | Tight (484 m) | 373 m → 614 m | |
| 7M 0550y - 7M 0660y | 🟠-🟠🟠🟠-🟠 | Moderately Tight (638 m) | 605 m → 698 m | Blackheath Tunnel |
| 7M 0660y - 7M 0770y | 🟠-🟠🟠🟠-🟠 | Tight (428 m) | Blackheath Tunnel | |
| 7M 0770y - 7M 0880y | 🟠-🟠🟠🟠-🟠 | Tight (490 m) | Blackheath Tunnel | |
| 7M 0880y - 7M 0990y | 🔴-🟠🟠🟠-🟠 | Tight (392 m) | 228 m → 592 m | Blackheath Tunnel |
| 7M 0990y - 7M 1100y | 🔵-🔵🔵🔵-🔵 | Flat (3,261 m) | Blackheath Tunnel | |
| 7M 1100y - 7M 1210y | 🟠-🟠🟠🟠-🟠 | Moderately Tight (523 m) | 500 m → 542 m | Blackheath Tunnel |
| 7M 1210y - 7M 1320y | ⚪-⚪⚪⚪-⚪ | Straight | Blackheath Tunnel | |
| 7M 1320y - 7M 1430y | 🔵-🔵🔵🔵-🔵 | Flat (4,008 m) | Blackheath Tunnel | |
| 7M 1430y - 7M 1540y | ⚪-⚪⚪⚪-⚪ | Straight | Blackheath Tunnel | |
| 7M 1540y - 7M 1650y | ⚪-⚪⚪⚪-⚪ | Straight | Blackheath Tunnel | |
| 7M 1650y - 8M 0000y | ⚪-⚪⚪⚪-⚪ | Straight | Blackheath Tunnel | |
| 8M 0000y - 8M 0110y | 🟢-🟢🟢🟢-🟢 | Very Flat (19,718 m) | Blackheath Tunnel | |
| 8M 0110y - 8M 0220y | ⚪-⚪⚪⚪-⚪ | Straight | Blackheath Tunnel | |
| 8M 0220y - 8M 0330y | ⚫-⚫⚫⚫-⚫ | Extremely Flat (49,555 m) | Blackheath Tunnel | |
| 8M 0330y - 8M 0440y | ⚫-⚫⚫⚫-⚫ | Extremely Flat (20,152 m) | Blackheath Tunnel | |
| 8M 0440y - 8M 0550y | 🟡-🟡🟡🟡-🟡 | Moderate (1,232 m) | Blackheath Tunnel | |
| 8M 0550y - 8M 0660y | 🟠-🟠🟠🟠-🟠 | Moderately Tight (561 m) | 559 m → 563 m | Blackheath Tunnel |
| 8M 0660y - 8M 0770y | 🟠-🟠🟠🟠-🟠 | Moderately Tight (583 m) | 520 m → 648 m | |
| 8M 0770y - 8M 0880y | 🟠-🟠🟠🟠-🟠 | Tight (496 m) | 425 m → 559 m | |
| 8M 0880y - 8M 0990y | 🟠-🟠🟠🟠-🟠 | Moderately Tight (611 m) | 508 m → 688 m | |
| 8M 0990y - 8M 1100y | ⭕-🟠🟠🟠-⚪ | Moderately Tight (582 m) | 179 m → Straight | Angerstein Jn |
| 8M 1100y - 8M 1210y | 🟠-🟡🟡🟡-🟢 | Moderate (1,213 m) | 472 m → 5,109 m | |
| 8M 1210y - 8M 1320y | 🔴-🟠🟠🟠-🔵 | Moderately Tight (595 m) | 230 m → 3,216 m | |
| 8M 1320y - 8M 1430y | 🔴-🟣🟣🟣-🟢 | Moderate (1,614 m) | 262 m → 10,501 m | Charlton Jn |
| 8M 1430y - 8M 1540y | ⭕-🟠🟠🟠-🟡 | Tight (464 m) | 225 m → 795 m | |
| 8M 1540y - 8M 1639y | 🟡-🟡🟡🟡-🟡 | Moderate (1,131 m) |