# Alignment offsets

Alignment offsets are typically used at horizontal curves in a rail tunnel to ensure that carriage clearance is maintained when the track is rotated. However, they can be used anywhere along the tunnel alignment provided there is a valid horizontal alignment, vertical alignment, and template assigned.

The following diagram illustrates using alignment offsets to avoid carriage conflict with the design tunnel.

1 | Horizontal offset | 4 | Offset tunnel
2 | Vertical offset | 5 | Design tunnel
3 | Carriage conflict |  |

To add alignment offsets to the tunnel definition, see To add alignment offsets.