George opened the ticket and wrote:

R17879

Wiki says:
Curvature info (var 45)
Format: xxxTxBxF
This returns the amount of curvature between the adjacent wagon pairs. It is useful for train vehicles that normally tilt in curves. The curvature is the difference in direction between the surrounding vehicles:
F = for the front pair (previous wagon to current wagon, 0 if vehicle is first)
B = for the back pair (current wagon to next wagon, 0 if wagon is last)
T = for the triplet (previous wagon to next wagon; is zero in an S-bend)
Possible values ...

I would like to ask to make 2 more vars. one for DX and one for DY.
DX=X1-X2, DY=Y1-Y2 (The X location, The Y location of two parts of ARV)
May be 6x var, where the parameter is offset, >0 forward, <0 backward

Reported version: trunk
Operating system: All

This issue was imported from FlySpray: https://bugs.openttd.org/task/3281