Roadbed design & support, elevated or on the ground?This section is about the 2 basic types of layouts, and will try to help you decide whether your railroad will be elevated or not?This is your first decision. Items to consider:Will bending down to work on the layout, place trains, correct derailments, be a problem?Do you have drainage problems, get heavy leaf accumulation, or snow where track on the gound will be a big problem?Do you have pets or animals that will wreak havoc with your track?If you plan to run live steam, the greater attention the locos need may be a factor.Is your yard so "heavy" with slopes that grades would be a lot over 2%. Also steam locos run best on dead level track.Elevated layoutsElevated layouts are visually appealing since the trains are up higher and more visible. They are easier to work on. Your trains are closer to eye level and look bigger.They can also be a lot more work, especially initally. Many people need tons (literally) of rock or soil to elevate their track. Normally retaining walls are needed.If you plan to run steam, an elevated railway is almost a must, due to constant attention to water, fuel, and inspection. Steam locos really like level track, and this is easier to do when you elevate the track, unless your entire yard is dead flat. Options are posts with with wood or metal between them to support the track. Relatively inexpensive, not really pretty though. Be sure to use plastic or metal, not wood for the posts. Be SURE to put the posts BELOW the frost line.The other option is to build up the earth to the height you want, and this will almost necessitate retaining walls. When you do this, you probably want some sort of support underneath, since the earth will DEFINITELY settle. You can make "ladder" track (which is really roadbed), 2 parallel "ribbons" of wood (cheap but rots) or synthetic wood (expensive, support twice as often) that supports the track. You can then backfill with earth to make it look nice. The dirt, IF compacted well, will help support the ladder system. You can also make the ladder system self-supporting. I would not recommend wood at all. Roadbed on the groundThere are many different ways to support the rails. Most importantly, you will want something that weather, animals and kids do not make a maintenance nightmare. If you live in a mild climate, a shallow trench filled with small gravel might be all you need (works for me in San Diego). You need good drainage to make sure rain does not wash things away. For wetter climates, you might put concrete pavers under the track, or pressure treated lumber bolted together. One famous garden railroader makes poured concrete roadbed. (Hi Marty!) This works well where frost heave is minimal. For areas that get frost heave, you might have to add supports that go below the frost line. The best thing here is to contact fellow modelers in similar climates and visit their layout or converse with them to see what works and how much effort you have to go to. In general, the more stable your base, the more time you will spend running. Running long trains or reliable operation needs nice smooth trackwork that is level side to side and is free of abrupt bumps or dips.BallastBallast greatly improves the look of the track.There are many variations on the type of stone and size you can use, but follow these guidelines:Do not use any smooth, rounded stone, it will shift position.Do find stone with sharp edgesGenerally, the harsher the climate, the larger the stone you need.Do NOT use any limestone or oyster shell. This is very alkaline and can damage the track. Many people use a coarser grade for the base or sub-roadbed, with finer stff on top.Crusher fines or chicken or turkey grit works well and looks good, but can wash out under heavy rains.Some people mix glue or cement with thier ballast to keep it from blowing or washing away. Again, refer to modellers in similar situations. I use a coarse mix for my ballast. It is larger than prototype, just fits between the ties, but it locks in solid and does not wash out. Since I use stainless steel, my track cleaning is usually done with a garden hose!