The steam locomotive is based on a set from brick producer “Cobi”.
This 11-wide steamer is absolutely true to detail and one of the most beautiful locomotives I have ever built with LEGO or third party bricks.
The part quality of the original set was really great and impressive. But the problem with the Cobi set is, that it is a static model and not designed for operations on the layout. The original loco has a couple of severe design problems that prevent safe operations on the tracks completely.
Here are just some of the problems:
- The gears that synchronize the wheel axles have too much drag. This consumes too much of the available motor power, and leads to increased wear and noise.
- Mechanical design flaws in the coupling rod and drive rod.
- The main wheels on two axles are not even connected to the coupling rod.
- Coupling rod and drive tod are touching each other when the loco moves.
- The original design practically prevents operations on even wide curves.
- Not motorized.
- No lights.
- No magnetic couplings.
I searched Youtube and the web for modifications, but I found only a guy who had placed train motors under the tender, and pushed the unmodified loco ahead of it. That was not what I wanted, because you can see from the slipping driver wheels that loco is pushed. IMHO, a loco in that size and weight needs to have the motors in the loco itself. So I created my own ideas and accepted the challenge.
I thought I’d invest half a day, and then I’d have a nice and large motorized steam loco with lights, that I can actually operate on layouts. Nope… it took two full week to modify the loco in a decent way until I was satisfied with it.
The loco has now two LEGO Power Functions L-motors inside. With these motors, it has more than sufficient power. The loco is operated with an S-Brick, which is also integrated in the body of the loco. The SBrick also controls the front lights. Most of the design problems could be overcome with appropriate modifications. It can take R88 curves, though I recommend R104 as the minimum curve radius.
Here is a video that shows this beautiful creation in action:
Enjoy!