Please keep in mind I am NOT on the planning committee so only know what I hear from others, but there is quite a bit of narrow gauge track planned in the next few years. The joke out here is that until you see ties on the dirt with rails spiked to them, the track plan is still fluid.
For right now the fourth track at Grizzly is getting connected with only a few parts needed to complete the switch so Chloe can come out of the engine house and become operational. We have over 80 acres at OERM, (now being changed to Southern Calif. R/R Museum), so we have some space to run track. The problem is that our narrow gauge collection is up at the far northwest corner of the museum where the property is quite narrow up at the pie yard, so that makes adding additional track up there quite tight.
There is even some talk about putting in a dual gauge diamond across the main line, so we will see.