![Image](https://64.media.tumblr.com/ba6803a0aa66c6e0c8613361cce1979b/tumblr_inline_nr4yhwXeAL1spg4o9_1280.jpg)
This thing makes some of the tech WE have look outdated. AND THIS THING RUNS ON STEAM!!! Is it really that much of a leap to go from THAT along with all the other tech of TLA to what we get in Korra? Keep in mind that the Fire Nation would likely have shared it's technological advances with the other nations after the war and with the aid of Earth and Waterbending along with Toph's newly learned Metalbending it's really not that unbelievable that we can go from GIANT F#(K1NG DRILL to planes, trains and satomobiles. Hell, the most outlandish tech in Korra are the mech suits and Kuvira's Pacific Rim Mech and, again, a giant drill exists in this universe which, again, was powered by Steam.
I honestly don't get why everyone thinks that the tech in TLOK breaks the world building when TLA had tech that wasn't that far from what could come next. And again, keep in mind that people in this world have the power to bend the elements so it would make sense that they would be able to advance in a couple of decades.
Seriously, after the Drill I'm surprised Korra didn't have space ships.