A basic circle oval is one of the simplest model train layouts you can have as it will fit perfectly on a piece of plywood around 4×6 with only the train and track, and no background scenery or landscapes. This option is lacking in creativity and imagination but if you choose to go for this it will not look very realistic and is unlikely to keep your attention for any length of time. However, it would be an economical way to go about it.
There are a few more interesting layouts that move away from the basic and simpler options that you may favour to include in your model railway plan. These designs incorporate point-to-point and the out-and-home layout, and are adapted versions of the previous idea. The former aims to simulate the movement of real life trains which are continually in motion as they move from one spot to another. This is based on fact, because in real life railways have subsidiary systems and branches, with the main branch starting in one place then moving to another before stopping.
Most model train layouts include terminals as part of the railway system to allow the trains to turn around although the main line still runs from point to point, or from one place to the next. At the end of the layout, you will find switches and yards with a turn around at the opposite end. Unfortunately while the layouts can resemble actual railroads, the scale of mileage is not accurately duplicated in the railway system. If you use scenery in a good sized layout this will outweigh this inaccuracy although the same compensation cannot be gained in smaller systems as they do not give the illusion of space for more than one terminal.
Smaller layouts are better suited to out-and-home model railway layout as they only have a single terminal. This is actually a modified version of the point-to-point model train layouts and basically it just doubles back on itself so when the train departs the terminal it eventually arrives back through your landscaped scenery to where I started. With a little imagination, you can pretend that it is not the same one if left from and this way you can accumulate mileage between terminals for your model railway. The biggest challenge when you layout your model railway is to create realistic scenery around it that and when you master this you will achieve an impressive model train layout that will please all who come across it.