How to Make Realistic Water on a Model Railroad

Prepare the area where you want to simulate water. It must be slightly below the level of the surrounding ground and be very level, regardless of whether the surrounding area is level. Add any desired texture or objects to surrounding banks before moving on, and seal the bottom of the area that you want to contain "water" with spackle.

Paint the deepest area of the "water' with dark blue or black paint, the next deepest area with a light blue, and the very shallow areas with paint that matches the surrounding ground. Do not make clear rings or distinctions between these areas; use your brush to mix the paint around on the model, making smooth, natural transitions between deeper and shallower areas. Wait for the paint to dry.

Add some acrylic gloss medium to the water area. If you have a very deep area of water, you may want to add it in layers, applying one layer, waiting for it to dry, then adding another. The medium will be white and become clear as it dries. If you want smooth water, pour in the medium; you may want to thin it with some water, as well. You can also try smoothing it with a palette knife. For choppy water, use the palette knife or a brush to create a rough surface in the top of the "water" by stirring or pulling up the medium as it dries.