Risers are the support elements used to position track roadbed above the joists of model train benchwork. These supports give the greatest flexibility for scenery modeling since terrain can be modeled both above and below track level. The basic structure of this device is shown below.

Although the vertical support is shown as 1” x 2”, it can be wider, if needed, for more than a single track. The 1” x 1” cleat is used as a slight adjustment for height as well as a means for screw attachment to the roadbed and can be screwed to the riser before it is installed on the joist. As shown, it is slightly wider than the roadbed to provide a shoulder for support of scenery. Be sure to drill pilot holes for the screws to prevent it from splitting. Only one screw, driven at an angle as shown, is required for single track roadbed.
For multiple tracks, the configuration can be modified as illustrated here.

This construction uses a second 1” x 1” support. Two screws are used to fasten it to the joist, but only one is needed for the long cleat.
Making the single track assembly is quick and easy to do. Once the wood is cut to size, clamp the cleat to the 1” x 2” support making sure that it overlaps the top edge and is square. The cleat should create a space between the 1” x 2” and the sub-roadbed that is at least 1/8” as the drawing shows. Square the two pieces and clamp tightly. Drill and countersink two pilot holes through the 1” x 1” and drive two screws through into the 1” x 2”. The assembly is now ready to install. You may find it convenient to make a number of supports and mark the installation height on each one.
Position the support at the desired location and clamp it to the joist. The important thing at this point is to ensure that the cleat is level and at the right height before permanently installing the support. Once you are satisfied, screw everything down.