There has been wheelslip in TSW for a long time but it has never been caused by low adhesion on the rails. It was mainly caused by too much throttle when starting off before the brakes were fully released, noticeable mainly on a heavy train where the loco doesn’t have wheelslip protection, and was therefore not as realistic as what we will have in TSW2.
RSN - BR 143 DB - precipitation and wetness to max. Now go full throttle (or apply excessive power) You can notice the wheelslip also from the HUD. [43] KM/H within two red-bars. Those two red-bars are the sign our loco traction-axle is in wheelslip cause insufficient adhesion. Where the effective speed of the train it was about 5 or 6 KM/H. From a good PC you can notice also the sparks. This tip/feature work with almost all the TSW trains.