I have usually used masonite, which you can get from Lowe's or Home depot, on a wood frame,. Some panels are integral to the fascia, my main panel is hinged, so it can be opened up to allow access to the spaghetti bowl of wiring behind it. The main panel is painted glossy black, and then I used masking tape to mask off a diagram of each block. each block was then painted in in the distinctive color which is used to represent that block on my tab on car operating system, so that the colors associated with the different ares of the railroad are reinforced between the block system and the tab on car operating system.
I use DC, with a block system. . the blocks are controlled by rotary switches, which I got years ago from radio shack, back before their main business was selling cell pones. My RR is extensively documented in the logging , mining, and industrial section, and there ares some pictures in there. check out that thread, and if you have some specific control panel questions, ask them there, and I will drag my camera up there and take some more pictures to help explain my answers.
Here are 3 control panels I built.
The big one has toggle switches and switch studs built in.
The small ones have Atlas cab switches.
The construction is masonite hardboard with a wood frame on the big one. The big one is hinged so that I can get behind it; it will also slide back onto a shelf but that almost never happens.
I live near some good electric/electronic parts stores where I can buy the switches that I need.
Some people have luck with clear plexiglass.
There are no ignorant questions. The ignorant wish to stay that way , and thus ask no questions.!
Same stuff. Mr Mason was working on making a fibre insulation board, and had some wood pulp in a press. he went to lunch, and forgot to tun off the press; and Masonite was invented. as flexible stuff it makes a great material for fascias and backdrops. it will curve pretty well as it is, and if you soak it in water, you can curve it very tightly. for control panels it is useful because it is smooth on one or both sides , can be painted to a nice finish, is thin enough to mount switches into it, and is easy to work with with standad carpentry tools.
I run old school DC. I have nine blocks. each block is controlled by a six position rotary switch. Currently I have four functional throttles hooked up to this system. I have room to add more, but it is hard to gather four people insane enough to attempt to operate this monstrosity. there is room to add another two throttles, but there really is not room is the aisles for four operators.
On mine the track diagram on each block in in a separate color. this color corresponds with the color of the tabs for my tab on car operating system, helping to reinforce the systen defining which car goes where.