Welcome to SimSig where you are in control of the trains! To start with you'll need a PC running Windows Vista, Windows 7, Windows 8, Windows 8.1, or Windows 10 - or an appropriate emulator for Linux or Mac.
Start by going to the System Files page and clicking on the Download link.
Click on the Save As... button that comes up. This varies according to your browser so it might say "Run" or "Save".
Windows will ask you if you want to allow this app to make changes to your device. Click Yes and then follow the installer dialogues through to its conclusion. Congratulations - SimSig is now installed!
But you need some simulations. Recent versions of Windows show recently installed programs in the Start Menu so find SimSig Loader and run it. Click "Check for updates" which also lets us install some new simulations.
Your list of available simulations will vary from the screenshot depending on what is available when you run it. Tick the simulation(s) you'd like to install and then click Next through to its conclusion. You'll then be taken back to the Loader screen ready to play some games.
Next: Playing SimSig