Why Marklin Steam Engines Runs Better Backwards

Most Marklin steam engines that have side rods have the alternate wheels lift up when the loco is moving forward. This is done to make up for the backlash in the gears. The backlash in the gears make the wheels closest to the motor to start spinning before the furthermost wheel starts to spin. This will cause the side rods to lock up. To compensate for this Marklin designed the alternate wheels to lift up in one direction and move down in the opposite direction. You will notice lockup sometimes after cleaning the loco if the gears are not aligned right or the loco will run only in one direction and lockup in the other direction. You will need to then turn one of the wheels backward or forward by one gear tooth to align it right.

The two movies below show center wheel of the Marklin loco lift up when moving forward and pushed down when moving backwards. This causes the traction to be improved when the loco is moving backwards.