Maybe the steam models belong in a different thread.
For me, what I admire most is the work the builders have put into them. The modelers seem to be mostly retired machinists etc who have thousands of hours invested before their baby runs.
I spoke to one owner who told me he has about 2,000 hours into just maintenance of a 2-8-2 scale model that the original builder 40 years ago spent some 5,000 hours creating.
My cousin, a retired electronics tech, (and patent owner) has put a lot of work into the signals system that is as complex as a real railroad. Interlocking go/no signaling, remote operated switches that automatically halt a train facing a switch open the wrong way, live communication system, lots more.
The craftsmanship on everything is amazing.