One of the most entertaining and challenging things I've done with MSTS was with the Sandpatch addition. In this activity I was in control of a pair of helpers pushing a train of loaded hoppers up a hill. I let the train reach the top and then cut the hoppers from the lead units and then cut off the helpers and backed them up. The string of hoppers began a free roll downhill following the helpers. I sped the helpers down as fast as possible to a siding pocket, parked the locos, reset the turnout, and waited as the runaway hoppers came and rolled by on the main. Then Ifired up the locos and caught up with the hoppers on the fly. Not exactly an assigned task of the game but fun (and no derailments).
Ralph