Some vendors do indeed offer rail systems. Strong Hand Tools, Siegmund, and Bluco all have floor mount systems. However, they are extremely expensive.
They have floor-mounted, machined rails that can either be surface mounted (creates a tripping hazard), or recessed (requires concrete work). Then you order special legs for the table tops which are designed to roll along the rails and be pinned in place.
If you don’t absolutely need a rail system, there are far simpler and less expensive ways to accomplish this. For example Texas Metal Works offers all of the fabrication tables with casters, leveling feet, or both. If you opt for both, you can roll tables into position, and then use the leveling feet to level them up when you have them where you want them. Just takes a few minutes, and you don’t need to tear up the concrete in your facility and spent tens or hundreds of thousands of dollars on special rails and legs.