Steam will usually automatically download any content you have purchased/redeemed a Steam key for but in the rare occurrence that it doesn’t you should try the following steps:

  1. Open the Steam “Library” tab from within the Steam client.
  2. Right-Click on Train Simulator
  3. Select “Properties”
  4. Select “DLC” from the tabs along the top
  5. Ensure a “tick” is placed next to the item you wish to download and install
  6. If the “State” updates to “Installed” after a short delay your item has now been downloaded and is available in the game

If the “State” still shows as uninstalled after waiting a short while please follow the below steps:

  1. Clear your download cache within the Steam client: https://support.steampowered.com/kb_article.php?ref=3134-TIAL-4638
  2. Go to the following folder (default location): C:\Program Files (x86)\Steam\steamapps\common\
  3. Delete the "Steamworks Shared" folder (if you have it; be sure to check your other drives if Steam is not installed to your C: drive)
  4. Go into the folder for Train Simulator and delete the "_CommonRedist" folder (if you have one)
  5. Verify the Integrity of your game files, a guide on how to do this can be found on: https://dovetailgames.kayako.com/Knowledgebase/Article/View/41/15/how-to-verify-the-integrity-of-your-game-files
  6. Re-launch Train Simulator

You should then find that your content is now downloaded and available in the game.

If you find that the content is still not installed we would suggest contacting Steam Customer Support advising them you have tried all of the above steps: https://help.steampowered.com/en/