Class 20 can't take power when rolling backwards!! Both versions RF and the newer one. I assume this is a bug due to the dual cab setup, but ??? To test.... Start on an incline (Bromsgrove is an easy one), master key on, reverser to forward, release brakes, allow train to just creep backwards down gradient, attempt to apply power to correct and move forward, nothing. Only way to get amps again is to come to standstill, or have the reverser in the direction of travel. Tested on other locos and could not replicate, they all take power fine when starting to roll backwards.
Most of them do to an extent, just the 20 occurs at a lower speed due to the lower gearing. Class 31/37/45 etc its set to not allow at -2.3mph for the direction of travel, Class 08 and 20 its set at -0.475mph It's just to stop bad things from happening when you do, aka idiot proofing. Theres a particular prevalent bug where the loco is effectively launched into orbit if you apply power the wrong way while going past a critical speed in reverse, so the logic is added to gaurd against it. Plus in all likelyhood it would likely trip the overload doing it in reality anyway. Basically just don't!
