Route duplication offers an efficient way to compare how different options will affect routing between the same locations. To duplicate a route including all stops, carrier information and options, click on its route entry window to activate it and select the Routes tab > Duplicate.

After the route is duplicated, you can make changes to the Route Options or add or change the station stops in the route. Select Run and PC*MILER Rail calculates the new route. 

Both routes are shown in the map window. Their color matches the color of the left-hand side of the route window. Route 1 (blue) was run with Route Options > Route Preference: set to Practical. Route 1 - Copy (brown) uses Shortest routing.