Let’s pretend that I have my joists ready and want to build risers. How do you guys do to get every riser at the same height (if that’s what you want) and leveled? Please tell me step by step how to do it. I have seen some people using laser to get everything leveled. Black and Decker have some cheap lasers. Good or bad? I just found something interesting: When installing the risers, the first ones should be spaced no farther apart than you can level. For example, if you have a 24" (600mm) level, then these risers should be no more than 24" (600mm) apart. This allows you to set the riser-tops by leveling directly from the one to the next. But what does it really mean?
I use a lot of clamps and square drive screws. When I get a section to work, using the clamps I add the screws. After the track is laid I can adjust certain risers by unscrewing and raising/lowering to taste. A tape measure helps, but I just look at it and get it right by eyeball(thats how the prototype worked).
I found that a torpedo level comes in real handy for this. I clamp the riser to the support, then drill and screw the subroadbed to it. I repeat the process for the next couple of risers. When I have a couple of them ready, I use quick clamps to hold the risers in place, using the level. When they’re level in both planes, side to side AND front to back, I screw them in place to the supports.
Install first riser using a short level or plumb bob. Install the next one (16", 24" or thereaouts away), place a 4 foot level on top of both risers and adjust loose one for level. For a grade, place a shim of proper thichness on top of one riser. Fasten second riser. Install third riser using the level on all THREE risers (unless on a tight curve). This will assure a smooth grade and help eliminate compounding errors.
Check level accuracy by turning it over or end for end and rechecking the position of the bubble. It must be the same or the level is out of calibration.
Real railroads were built using transits and story poles so a laser level and ruler should be perfectly fine “modeled” substitutes.
Electro, I found myself using clamps and a meter-long framer’s level, the kind that a construction worker would use framing a house. So, you need to start where you know a fixed height will be, such as your yard, and then work outward in both directions if it will be a smallish loop. You should know, beforehand, where you maximum height will be on the layout, and how the grade will get you there. Will it vary in places, sometimes 1.5%, other times nearer 2.5%? Will it be consistent between the vertical easements? These considerations will determine where and how your risers are fixed. In my case, besides the clamps, I used a traversing laser leve canted at an angle so that the wide, thin, beam gave me an approximation of the grade in an arc of about 30 deg. Note that, since the tripod or mount of the laser instrument will be an altazimuth mount, as you swivel the laser the path it shows will lose accuracy the greater the arc you make without actually reorienting the mount to follow the risers you place. To see what I mean, place your tilted laser facing one wall, then sweep the laser over 90 deg. You will quickly realize that leaving the mount in one position to grade your roadbed will result in a grade much steeper than you want.
Another method, if you wish, is to place two risers in the approximate grade position that you want, and place a piece of flat plywood between them, set on each riser. Use the canting screw to cant the level mount to the grade you want (in degrees), and then place the level in the centre of the two risers with the mount facing exactly 90 deg to the axis of the risers and the level along the axis of the grade. If your risers are set to the correct heights, the bubble should read level. Unclamp and adjust the risers as you must, then screw.
For grades, I used a 24" level with a wood block under one end. For 24", each 1/4" of block is 1% of grade. I didn’t have a longer level, but an absolutely straight board would work.
I try to fix the ends of the grade and match the intermediate risers to them.
Trust your level. I wondered why the riser heights weren’t working out right; after installation I remembered that the basement floor slopes.
Use lots of clamps!
Someone cuts a vertical slot in the riser so that it can be adjusted.
I use a Black & Decker pendulum laser level and a six foot (or four foot if the space is shorter) bubble level. A bubble level doesn’t work well for shallow angles (or at least I can’t read it that accurately) - I set up a 15-foot long grade and found out at the end I had a clearance issue with the track below. I set up the pendulum laser level (that’s just a level where the laser sits on a hanging pendulum. Very accurate, as gravity automatically levels the laser) and align the bubble level using leveling blocks so that the laser line just touches the top or bottom edge of the level (I use the bubble level because they’re very straight). In that 15 foot straight run, I was 3/4 inch off from where I read the bubble level! The pendulum laser was less than a hundred bucks, as I recall.