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Motorized LEGO Roller Coaster Train

September 6, 2019


Hey everyone, Jason here. Ever since LEGO released their new roller coaster track system I’ve been wanting to build a
motorized train for it, and for this particular train I wanted to design it
to be able to handle all of the possible features of the coaster system, so it can
handle going up and down the steep slopes and all of the various grade
changes that come along with that. And that imposed a few restrictions on the design, for example I couldn’t make the cars very long otherwise the front and
back of the car would hit the track as it went through one of these dips. And
those dips along with the really tight curves also requires that there be
enough space between the cars so they don’t interfere with each other. You can
see that the front and back car almost touched the motor when going through the
dip, and similarly the sides almost touch when going through the curves. I also
thought it’d be kind of cool to throwback to the old monorail system by
putting the motor in this small central engine car, and this also has the added
advantage of being able to easily run it in either direction. So let’s take a look
at how it works. I have this standalone model of the
engine car to show you what is going on and the drive system is pretty simple.
There are two axles that drop down below the chassis of the engine car, on either
side of the track, and each one of those axles drives a rubber tire alongside
this lower sidewall of the track system. And it’s actually a really secure fit. I
think you could even do some kind of suspended train this way as well. For
tires I’m just using these basic small rubber tires which are pretty common, and
normally they come on these little small wheel hubs, but they also happen to fit
on these Technic half bushings which makes it really easy to drive them using
a standard Technic axle. The spacing between the tracks is a little bit odd
so on the chassis the axles have to be four and a half studs apart and so to
achieve that I have one running through a standard Technic 1×2 brick with a
single hole, and the other one is running through a
Technic brick with two holes. As a result the engine car isn’t perfectly centered
on the track it’s shifted about 1/4 of a stud off-center. And the connection to
the motor which I’ve just removed here so you can more easily see what’s going
on is through this central cross axle, which transfers power to each of the
drive axles. For the other cars, I just have them mounted on the standard roller coaster car frames since they work really well with the coaster system, and
to connect the cars together I’m using this small shaft with a ball joint on
either end. Since the train is going through curves on the level and also
going through grade changes you do need two degrees of freedom in that
connection which is why I’m using the ball joints. And that is pretty much all
there is to it. I have created building instructions for
this basic train chassis which you can find, along with some other information about assembling your own train over at jkbrickworks.com. I’m actually looking forward to experimenting with some other train and engine designs, especially for just a flat track configuration. I think removing the steep hills will allow for some more flexibility in the train design and I’d love to design a longer El
train that would look good running through a city display. I just need to
get a couple more, well a lot more, of these straight tracks. These are the only
two I have right now. If you want to see more original LEGO designs, be sure to
subscribe. As usual thanks for watching, keep on building, and I’ll see you next
time.

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