Feature: [NewGRF] Maximum curve speed modifier for rail vehicles #9346
Motivation / Problem
Prior to 0f91cb0, rail type's
Currently, the only way a rail vehicle can control its curve speed bonus is via the tilt property, which is a flat 20% bonus. There are no other ways in which the original behavior can be recovered. NUTS (and possibly other NewGRFs) relied on that behavior quite heavily.
This PR fixes the stated problem by introducing a new rail vehicle property:
The way this property works is analogous to tilt. Each part of the consist has its own
Moreover, NewGRFs can also affect
This change also expands the possible design space compared to the original behavior: NewGRFs can provide powerful trains that travel slowly in curves; wagons that, when refitted to fragile cargo, must travel slowly in curves; and so on.
NML support: OpenTTD/nml#222
No known limitations.
Checklist for review
Some things are not automated, and forgotten often. This list is a reminder for the reviewers.
Together with @V453000, we've also prepared a modified version of NUTS and a savegame that showcases positive and negative curve speed modifiers as well as curve speed mod callbacks.
I went a bit further and replaced all TRAIN_FLAG_TILT with increased curve_speed_mod. This is so much cleaner and I can't wait when I get the courage to finetune the values further.
Not sure if it's helpful at all (probably not), but I'll provide it here too.