How Do You Set Up The Class 390 For A Unit Drag?

Trying to do a Class 390 and 37 unit drag but can't get the breaks to work together. Is there a way to fix this, I've tried the ETS brake dial and it didn't help. I've had to turn off breaks on pendolino but the it takes 4 miles to stop from 60mph. Can anyone help?

 

Tried it myself but I couldn't even get the brakes off in the first place.

 

Players report that you can get going, but the brakes are basically non-functional. So it seems it's a bug of sorts.