A few of the choices you need to answer before you get started are:
What scale would you want to work with?
What era or region of train type?
How much space do you have for a layout?
The two most popular scales are HO and N gauge, they would have the most accessories available for building a layout. With N gauge you could make a nice little layout on a desktop size area or smaller. With HO scale, you would need at least 2 desktop sized areas to make a small layout on.
A few of the choices you need to answer before you get started are:
What scale would you want to work with?
What era or region of train type?
How much space do you have for a layout?
The two most popular scales are HO and N gauge, they would have the most accessories available for building a layout. With N gauge you could make a nice little layout on a desktop size area or smaller. With HO scale, you would need at least 2 desktop sized areas to make a small layout on.