LGB Mikado - Part 3 Design Flaws

After the first series of Mikado had serious design flaws LGB set to rework the engine design. In a first attempt  the coupler was fitted to the axle by making an axle with rectangular ends so the coupler could fit and transport movement without slipping.

This change had ramifications that required more design changes.

The first joint between the motor and the first cardanic shaft proved to be the weakest part of the design as the plastic pick-up was not able to handle the torque of the motor and carry the mechanical load. Consequently the joint between the motor and the first cardanic shaft was completely redesigned: the star-like brass wheel on the motor axle was replaced by a rectangular brass bolt. The cardanic shaft got a plastic pick-up shaped to fit the brass bolt.

re-designed cardanic coupler
copyright by TrainCraft by Klaus

This second re-design  however had a flaw of its own. As the star-like connection provided guidance (in the center line) for the first axle the new design did not. As the first axle tended to wobble, this wobbling movement was transported to the other end of the first cardanic shaft; which was only kept in place by plastic guides within the motor block and its top lid. Pretty early on these plastic guides wore out giving the axle more play than designed. This resulted in a constant rattling noise from the rear motor block.

new rectangular brass bolt
 copyright TrainCraft by Klaus

The ultimate and last re-design called for a total re-work of the two motor blocks. The first and last cardanic shafts were equipped with two ball bearings that now measured 12 mm (compared to 10 mm earlier in diameter). With the first axle being properly guided the rattling noise was completely eliminated giving the whole drive train an exceptionally smooth operation.





Production numbers for the Mikados No 20872, 21872 and 23872 (shown below in sequence)  had varied between 500 and 800 in the first production run. They were re-manufactured  in Summer of 2002 with all above listed re-designs. To some extend  just to replace those locos the customers had sent in. And some to fulfill increased sales for this Mikado type.

That means that there are still quite a lot of Mikados out there that already do or will produce one of the following failures:

the engine runs slowly or stops while the motor is audibly working  (the first generation plastic pick-up/coupler turns on the axle).

the engine simply stops with the motor running with grinding noise  (first generation plastic pick-up is worn out).

rattling noise in the drive train  (axles start wobbling because plastic guides are worn out).

These failures do also occur when the Mikado is operated in a 24/7 modus. If you are a heavy driver of your LGB loco(s) contact Klaus for POM treatments. It's a professional and easy fix to 'permanent operation' even for a Mikado.


With the fixes in production LGB set out to manufacture the next Mikados, the No. 25872 and the LGB # 24872 which was manufactured exactly one month later than the 25872....


+++++++++++++++++++++++++++ to be continued.......................................................