I recently completed my collection of VT 11.5’s with the addition of 88733 + 87933. Sets 8873- 88735 are stellar sets that have been continuously modified by Marklin not just in design but function that being electrical function with the couplers that link each car together. Keeping things simple and uncompromising are Marklin Z attributes, one need only look inside one these loco’s to fully appreciate the good functional design, they are easy to take apart and put back together with side rod locos being an exception. Well this is a first, I just received a lightly used 88733 (mint cosmetically) with one end car not working properly, the motor turned over very sporadically thereby becoming a ball and chain to the working end car. I have never encountered a faulty Marklin z motor before so discounting everything else from electrical shorts, mechanical and other electrical misalignments seemed to make sense, it is after all fairly simple to trace the electrical flow from the track to the motor. To my great surprise the problem rested with the motor and a very poor repair to a brush, even with new brushes the motor was rubbish. Not sure of its prior history, but I would not be surprised if the poorly repaired brush had something to do with the motor being fried. If the gears and wheelsets are moving freely, circuit board is not cracked and black screw is present that attaches board to chassis, wheels are clean, and whiskers are properly in contact with motor brushes then the problem is most likely the brushes themselves and maybe(?) the motor.

Side note: If you have congealed oil otherwise referred to as “hardened oil syndrome” (HOS) considered using the synthetic oil Labelle #108 which is a lightweight oil and plastic compatible as your oil of choice.