Interesting question. Old school here;
Target wires hung from the overhead on piano wire with fish plate weights to steady them in the pit. A number of ways to secure the wires, but once set and secured, they’ll not move. Brackets were set (and anchored) to centerline off of these wires. Rail gage with 1” dot from the rail face was used.
Yeah two stops were easier with the plumb, but a straight piece of 3/4” conduit beveled on one end was used for the BG stick and rail facing one to the other no matter what the number of floors. I’m sure there are more “modern” ways today to achieve a plumb and faced rail job which (should) equals a smooth ride. Never used a level of any sort for rail install.

I’d pretty much second that except we did always use at least a 4’ level to “rock” the stacked rails straight before nailing down the fish plate bolts. I’ve never been a fan of lasers for rail jobs. The PLS lasers they were using 10 years ago weren’t that accurate but I wouldn’t be surprised if there was something good enough now.

I'm a huge fan of plumb bobs. If it's not windy, plumb bobs don't lie. I never did trust lasers, and I always found it easier to see a string line than that invisible laser

And I also like conduit for checking dbg.

Although I never used one when installing, I now use a bosch laser tape measure somewhat frequently for various things like estimating lengths of cable for a job or filling out survey forms. Those things are incredibly accurate (to the 32nd of an inch) and I wouldn't hesitate to use one if I was installing again. Man how nice it would have been to simply hold it on the rail bracket and get an instant measurement that's accurate when setting up my top rail brackets instead of twisting and stretching trying to hold a tape measure in place, no bowing in it and read the darn thing accurately while on the extension ladder jammed at an angle into the shaft corner. This is what it must feel like to be a retired mechanic that installed elevators with square bolt heads and all hand tools watching the new generation throw stuff in twice as fast with battery powered impact wrenches and be thinking how nice it would've been to have had that modern technology when they were doing it.

Good info here! Here’s a trick I was taught that made me go WOW that’s the easiest way to do that. When you want to find center of rails to do fronts off temp skip. Get a stick of 3/4 conduit notch about 1/2 inch off one end 1/2 way thru. This end goes on rail and out the opening. Put a pencil on the end and draw an arc on the floor. Now do the same on the other rail. The two arcs will cross each other in 2 places. Draw a straight line thru the 2 Xs back to edge of hoistway. This will be dead center of your rails every time. Length of conduit will depend on how far back your rails are but you’ll see real quick how long you need.

laser and a Plum-bob