LEGO has introduced an all new roller-coaster play system in 70922 The Joker Manor. We discussed it briefly in our review of the full set, but we felt the new roller-coaster rails were important enough to merit a post of their own. As one of TBB’s least Technic-centred members of staff, I found it was great fun attempting to add Power Functions to the rollercoaster and—health and safety aspects aside—it turns out it’s also rather simple.
First, a recap of the new purple tack sections supplied with The Joker Manor. The system includes five new rail sections — a short straight section, slight elevation, concave elevation, convex elevation, and quarter curve. There are two each of the first four rail sections shown and four of the quarter curve sections to complete a short loop around Joker Manor.
There are three rollercoaster cars in this set, and the cars themselves are constructed from a single Lime body part with two sets of wheels which simply click into place beneath the cars.
Importantly for this exercise, the underside of the cars has a central pin that extends between the track and allows the cars to connect with a Technic chain link to pull the car along. Other types of tread links may also be compatible, but the classic Technic chain was the only link style that I had in sufficient quantities to test.
Discussion with other senior technical and engineering colleagues at TBB lead to the supply of this conceptual set of instructions, kindly provided to assist me in my Technic endeavours. Feel free to use these detailed instructions to build your own motorised LEGO rollercoaster. 
For this test setup, I kept things very simple with a Power Functions battery pack, a Power Functions M-motor, two gears that were in The Joker Manor and some Technic chain link.
My version of this upwards chain link portion is not perfect, I know, and I welcome suggestions to improve it. The main aim was to prove the concept that the rollercoaster could be powered using current Technic parts, rather than provide a perfect solution to the numerous issues of powering a LEGO rollercoaster.
To remove the ‘distraction’ of Joker Manor, I roughly set up the track in a complete loop using a selection of supports to hold key parts in place. During the series of tests, the height of each support could be easily altered by adding or removing plates to ensure that the cars would complete the circuit powered by momentum from the top of the hill. The tracks allow a bit of fudge in the system as they flex a little when connected in a complete loop.
To my great, child-like excitement, the test and setup worked and soon a LEGO rollercoaster was cruising around the track, connecting with the chain link (mostly without issue—although there were some crashes and derailments) and continuing on its winding journey. Success!
Now someone with more engineering knowledge and Technic construction skill can make it prettier and more effective…but it works!
I can’t wait to see where LEGO takes this new system. As we mentioned in the review of The Joker Manor, it’s our guess that a Creator Roller Coaster set is coming in the near future, though LEGO has yet to announce any future plans.
The LEGO Group sent The Brothers Brick an early copy of 70922 The Joker Manor for review. Providing TBB with products for review guarantees neither coverage nor positive reviews.