What's the one item you want on your layout, but don't yet have (and isn't a train)?

STL union station still has a few tracks (4?) under the shed that are used for charters and special holiday train excursions. They usually do a polar express mini excursion, about 1 hour. They've also done a Charlie Brown themed Halloween/Thanksgiving mini excursion. We've been a number of times with our kids. The events seem to be very well received. 

Jennifer Lawrence...

RE:  St. Louis Union Station.

My uncle was one of the contractors for the renovations, but I was in college at the time and never got down there to visit, alas!

I do have one set of the TRRA copies of the track plans; they are huge!  I need to get them copied, as they probably won't last too many more years.  I need to get them to a place that has a big enough scanner bed for the job.  My ex-wife's grandfather was a TRRA switchman and signal maintainer for all his adult life.  These plans are one memorial I have of that grand old guy.  The other is a TRAA coal-fired caboose stove.

I'm in the want--a-turntable-&-roundhouse-but-don't-have-the-room crowd.

I'd also like to have a long, tall wooden trestle, but I have even less room for that than the RH/TT