| Junctions and other features | Running Lines | Stations, Signal Boxes and Junctions | Distance from Signal Box above | Loops and Refuge Sidings | Notes | |
|---|---|---|---|---|---|---|
| Maximum permissible speed 40 m.p.h. | ||||||
| 1 | ↕ | Hatfield No. 3 | – | |||
| 2 | ↕ | Welwyn Garden City Station | 2m 1005yds | |||
| 3 | ↕ | Ayot | 1m 1364yds | CL 35 | ||
| Wheathampstead Station | ||||||
| 4 |
 |
↕ | Harpenden East (L.M.R.) Station | 5m 214yds | ||