After designing your model railway layout, you may want to consider making your own model train table. The best way to start is using an old or unused table or plywood. But using these has its drawbacks.
For example if you are using an old table, you may encounter problems on where to place the holes in drilling your electrical connections like the switches. This is why that DIY table is preferred by most modelers. If you build your own table, you will have no problem in making electrical connection route. You can also directly build your scenery to the table.
The main part of your planning stage is deciding on the size of your model train layout. After you have decided on the size of the layout, then you can plan on where to place the scenery. From this, you will be able to work out where to put the support for the table and where to place removable flooring for easy access in retrieving the train in hard to get areas.
In designing your own model train table, you must consider creating interlocking sections if it is quite large. These will be an advantage when you want to disassemble and transport your model to other places.
You should also consider the height of the table. The height must be perfect in reaching derailed vehicles or in redesigning the scenery.