It's a shame the high line became a trail and wasn't bought by a historical society and become a railroad museum, oh well.
part of it is, actually. about 2.5 miles of it running south out of Belton is used by the Belton, Grandview and Kansas City [tourist] railroad; it basically parallels Highway 71, and in fact if you're timing is right you can chase the train down it. The line used to go much farther, but down past the current end-of-track there's an ancient wooden Trestle (which still stands, and can be seen through a break in the trees from Highway 71 if you know where to look), and unfortunately somebody (FRA probably) condemned the thing.
At one point it was run by the same group of guys who currently run the Midland Railroad our of Baldwin City, Kansas, and in fact they used to run some of the services with the same Rock Island E6A unit that's on the Midland now, or so I've seen on ancient YouTube videos; one of them, taken while the group was shunting Frisco Russian Decapod No. 1632 to rest on its display track, shows a Baldwin switcher of some kind...I want to say a VO1000...moving about as well. What happened to her I have no Idea. Speaking of which, I've talked to some of the guys who work at Show Me model trains in Grandview that I know, as well as some of the volunteers at Belton the couple times I've been there, and they've said that the 1632 is supposed to be restored to run; however, they've been saying that for the past 10-15 years (IE since they GOT the thing) so that's probably not going to happen. Honestly, they don't have enough track to get their money's worth if they ran the thing anyway; they'd end up spending way more on the fuel and water.
BTW, there's another steam engine there on display; Okmulgee NorthernNo. 5, a 2-8-0. She's got an interesting little story behind her; she was one of three locos built by ALCo on speculation of sale to a Cuban sugar plantation. It didn't pan out, and she wound up in Oklahoma instead. However, one of her sisters is much better known: she's numbered 97, and currently works on the Valley Railroad in Conneticut!