Since designing my ‘Roller Coaster Train‘ last year, I’ve been working on a new train to run on the roller coaster tracks that more closely resembles a typical commuter train. I call it the LEGO Light Rail Transit (LLRT) system and I loosely based the train design on Ottawa’s soon to be completed (any day now) Confederation Line light rail commuter train.
As I mentioned in the video, this train was designed to run only on the flat sections of the roller coaster track, which allowed me to be a lot more flexible in the design. As a result, I was able to build a more traditional style of commuter train with longer train cars and come up with a drive system that runs faster than my previous train design.
You can find instructions for the engine and car below. If you are planning to build your own version of this train, or some modified version based on it, be sure to read the build notes below.
As usual with Technic builds, it’s important to make sure all the drive axles and gears rotate smoothly as you are assembling them. If you press the gears together too tightly, it can cause excessive friction which can hinder performance.
If you design a train with only a single engine, I have found that it is only able to reliably pull two cars, primarily due to the friction going around the tight curves. I would recommend putting all the electronics in the car immediately behind the engine.
I have also found that making the engine as heavy as possible can help improve performance, as it increases the friction between the drive wheels and the track rails. In fact, I think you could fill some of the empty space in the engine with small weights of some sort (coins for example) to increase its pulling power. Alternatively, you can try to make the cars as light as possible. It might sacrifice some of the aesthetics of the train, but it will improve the performance.
If you use two engines like I have shown in the video, where they are facing in opposite directions and connected to the same motor output, you will need to mirror the drive gears on one of the engines so that they will both run in the same direction.
Regarding the wires, you need to be mindful of how they are running throughout the train. You’ll want to make sure there is enough slack in the wires running between the cars, and between the engine and the car behind it, to prevent any excessive pulling as they go around the corners. This can actually be a bit tricky to get right, and you might have to play around with how the wires are running.
If you plan to run the train for long periods at events, you will probably have to dismantle and clean the drive axles at the end of each day. I have noticed some buildup of dust over time. You can actually just pull off bricks holding the train wheels from underneath to do this.
If you would like to have some elevation change in your layout, I have found that the train can handle an increase in height at a rate of 1 brick per track section without too much trouble, which is what is shown in the video. I haven’t tried anything steeper than that.
If you do build a train based on this design I’d love to see it!