Is your feature request related to a problem? Please describe.
The train's speed can't be a custom number.

Describe the solution you'd like
When we click on a siding of a depot, we can edit both the train's max speed and the acceleration.
If max speed is greater than rail's speed, the train's speed will be the rail's speed.
If max speed is smaller than rail's speed, the train's speed will be that max speed.

Additional Information
No.

We Already got Custom Acceleration.

I want to modify the train's max speed.