You are correct that there are active railroads on both sides of the crossing. The line to the west is a UP branchline, used to access various customers in the Las Vegas valley. The line to the east is now home to the Nevada Southern Railway, an operating arm of the Nevada State Railroad Museum.
Basic story is, when NSRM built their main campus in Carson City, it upset politicians from the southern end of the state, who more or less demanded a railroad museum of their own. The state bought the outer end of the old UP Boulder City branch, which itself had been originally constructed to support the construction of Hoover Dam. All freight business out of Boulder City dried up, which made it available for purchase. The state purchased a substantial collection of equipment from the remnants of the old "Heber Creeper" operation, plus accepted some donated equipment from UP and the military railroad operations in the area. The museum operates excursions in a push-pull fashion out of Boulder City up to a point just short of the crossing site, normally powered by UP #844 (no, not that one, but the GP-30) or an ex-UP NW-2. They have a small shop that is usually open to tours and a few static displays in the depot area, plus a fenced compound where most of the equipment is stored that is usually off limits to visitors (at least the times I have been there). They also have a few stretches of third rail track, and Dan Markhoff occassionally brings his ex-Eureka & Palisade #4 over the hill for operating days.
While the protection equipment is still there, the crossing has been closed for a long time. Re-establishing the crossing would require the blessings of NDOT (not likely easily forthcoming). There are possibilities that 93 may be re-routed in that area, which could reconnect the museum with the rail network and allow them to expand their operations. Until if/when that happens, they are worth a visit if you happen to be in the area.