Those who are buying Railworks and never had the predecessor Rail Simulator often have trouble installing the old packages into the new game. There are four basic package types;
1. Third party executable such as ClickTeam or Winzip self extractors, for those you merely need to point the installer to your Railworks folder.
2. Official addon installers that refuse to install when they can't find Rail Simulator. For these use the "Install Legacy Rail Simulator Addon" button in the package manager.
3. Official packager files with an extension ending in .rpk. For that use the regular Install button in the package manager.
4. RS_Tools packages. These have a RouteSetup.exe or Asset_Setup.exe file along with .xxx or .ggg files containing the data that originally got appended to the master files. Many route developers used this because it had built in error checking and made backups of critical files before overwriting them, so was more foolproof and failsafe than the official packager.
For .rpk files;
Start the Railworks launcher, select the package Manager tab, then click Install, NOT the Legacy Installer. Browse for the .rpk file, acknowledge the warning message, and install the same way you would an .rwp file.
For the ones packaged with RS_Tools you'll need RW_Tools;
http://www.rstools.info/page8.html
Once you have that installed use the converter to change the railsim installer. When unzipped a route looks like this;
That won't work in Railworks because it's designed to append the code from the Route_Setup.xxx file into the master Routes.xml file, which in Railworks has been replaced by independent RouteProperties.xml files in each individual route's main folder. So to convert;
Note it says "select the folder containing the RouteSetup.exe", if the guy buried that inside three subfolders you need to go to the one that has the RouteSetup.exe.
When that's done go back to the folder and doubleclick on RW_RouteSetup.exe and point that to the Railworks folder. All the conversion has been done in that one step, RouteProperties.xml added to the folder, scenarios.bin deleted and all the code from that split up into the individual ScenarioProperties.xml files required by Railworks, so there shouldn't be any hacking required for these to work.
Railsim Port Ogden & Northern USA 2route from February 2008 installed straight into Railworks after converting the installer.