Version information:

• Platform: Windows 10
• Version: v21.08 to v24.10

Bug was introduced in-between OpenLoco versions v21.07 (7ec445f) and v21.08 (7aecfa5).

Describe the bug
When trying to place a steep curve, it fails with the following error message, even when the land should be considered suitable:

Can't build Narrow Gauge Track...
Raise or lower land first

This only happens when free-placing the track piece (i.e. "Select new start position for construction"); building it by continuing an existing track works fine.

To Reproduce

1. Load a game with narrow gauge rails available, such as "Swiss Alps 1930"
2. Open the narrow gauge track building tool
3. Select "Steep Slope Up" (the 45º one, not the 22.5º one) and Left- or "Right-Hand Curve (Small Radius)"
4. Locate a flat area of land
5. Attempt to place the track.

Expected behaviour
Track should be built

Screenshots

Additional context
I'm not sure if this issue is specific to Narrow Gauge or not, as I cannot find any other type of track or road that has Steep Slope Curves available.