Why do we need a baseboard?
In the early days of train sets these were usually to O scale, being this size most of the pieces of track and stock were of such a strength to resist being dropped, knocked over or stepped on, plus the fun of setting out the layout around chairs and other obstacles added to the experience. However as time went by the scale got smaller, we went to OO which meant the floor was maybe not the ideal place, so we moved to the table or worktop. The only problem with this was that most of these surfaces were used for other things, so the trainset had to be dismantled at some point. As we went even smaller to N scale this started to not be an option. The ideal solution would be to build a fixed surface which held the track in place and allowed it, if needed, to be moved in one go. The other thing with a dedicated surface is the train set can be evolved into a model railway as scenery can be added as it will always be there.
Materials and tools.
A baseboard is made of a frame or grid, with or without a top covering it, a look at each of these later. The basic material that is used for a frame is wood, other methods are available but we will concentrate on wood. Most people will use softwood, though hardwood is available - it is stronger, but more expensive and harder to work. Softwood is readily available from local timber yard or DIY shop and in general this is fine. When choosing timber make sure it is free from bends, kinks and large knots. Unless it has been fully seasoned (usually more expensive), the timber should be left to stand in the house for a few weeks especially if you have central heating. This will allow the wood to shrink before it is made into the baseboard rather then after where it may cause warping.
For the framework the most frequent used size is 2" by 1", but other sizes may also be needed depending on the type and size of the baseboard. Fixing is with screws, usually 1 1/2" or 2" flathead and white glue, designed for gluing timber.For the top surface, if one is required, there is a wide variety of materials, with the decision being made on availability, price, familiarity and weight of the board. Some choices are Sundela, MDF, Plywood and Chipboard, these can usually be bought in various sizes and widths.
Fortunately only a basic tool kit is needed, for cutting the frame pieces to size a saw is required. A handsaw is adequate, a tenon saw is a bonus for making neater joints, if you have a power saw this will make life easier especially if you intend to do loads of cutting. For making those joints neat, a square or mitre block is a must. A decent ruler and tape measure is required. A chisel is needed if you intend to make halve joints. A selection of screwdrivers. A hand drill or power drill, with bits, to make pilot holes for your screws and a countersink drill bit to keep the screws flush on the top surface. Sandpaper or an electric sander to keep things smooth. A good knife, and if possible a workbench. A good selection of clamps to hold the timber, you only have two hands remember.