Horizontal curvature for ELR BBS4 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 |
|---|---|---|---|
| 9M 1211y - 9M 1320y |  🟢-🟢🟢🟢-🟢 | Very Flat (8,541 m) | Very Flat (6,489 m to 8,852 m) |
| 9M 1320y - 9M 1430y |  🔴-🟠🟠🟠-⚫ | Moderately Tight (725 m) | Very Tight (233 m) to Extremely Flat (25,478 m) |
| 9M 1430y - 9M 1540y |  🔴-🟠🟠🟠-🟢 | Moderately Tight (699 m) | Very Tight (300 m) to Very Flat (10,209 m) |
| 9M 1540y - 9M 1650y |  â•-â•â•â•-🟡 | Extremely Tight (137 m) | Extremely Tight (<100 m) to Moderate (1,236 m) |
| 9M 1650y - 10M 0000y |  â•-â•â•â•-🟠 | Extremely Tight (140 m) | Extremely Tight (<100 m) to Tight (414 m) |
| 10M 0000y - 10M 0110y |  â•-🟠🟠🟠-🟣 | Moderately Tight (508 m) | Extremely Tight (181 m) to Moderate (1,421 m) |
| 10M 0110y - 10M 0220y |  ⚪-⚪⚪⚪-⚪ | Straight | Straight |
| 10M 0220y - 10M 0222y |  ⚪-⚪⚪⚪-⚪ | Straight | Straight |