The toughest challenge here has to be the powered carriage itself. Getting the motors to help the locomotive away from a standstill and then let go, so the locomotive pulls with almost no resistance, is a genuinely tricky bit of engineering, and the maker has built one motor into each bogie that can detach from the wheels and reattach again. On top of that, the axles used to snap now and then since each one is made of two halves joined in the middle, and a 3D printed sleeve now covers both halves of every axle and ties them together much more firmly.
Elsewhere in the build, the snowplow has been redesigned to be more dependable and runs on fewer servos than before, and it reportedly performs better than the original version. The track switch has also been upgraded: it can now be triggered from a button in an app rather than by hand. The interior is being recreated digitally to match the carriage seen in the show as closely as possible, with online pictures of the sets as inspiration. Fittingly for a big layout, it sits at 1:45 scale on 141 mm gauge track, with a Lego figure placed alongside for a sense of size.
The grey bodies with the circular W emblem on the nose look right for the Snowpiercer locomotive, and the LED lighting along the headlights and roofline must look great running on that makeshift track on the wood floor.
There is still plenty open: the back of the carriage awaits 3D printing and lights, the interior design is not finalised, and the carriage motors recently stopped working, probably a fault in the motor driver, with a fix being attempted. The two first class cabins, double what the show's carriage holds, will be interesting to see furnished.