For your train trips, if I understand what you want from your 1490 correctly, I think it will give you what your looking for fairly easily.
While you travel, if you want to create and save a particular place as a waypoint, all you need to do is tap the vehicle icon on the map screen. This will bring up the "Where Am I" screen and from there you tap "Save Location". Give the location a name and it's saved in your Favorites.
If your looking to keep logs of your traveled routes, either by vehicle or train, and view/save those so that you can view them in Streets and Trips 2010, Google maps etc., this also can be done easily on the Nuvi. From the map screen, tap the speed icon to bring up the "Speedo screen". Press the speed read out in the middle of the round speedometer for 5+ seconds and the "Diagnostics Page" will open
Now tap Diagnostic Logging and the Engineering Mode:Logging Control page will appear. Tap "Start Logging" and on the Data to Log screen, tap GPX and then Start.
You will now notice in the top center of the map screen a counter. This is the log time counter. The movement (track) you are traveling is also being written as a trip log to the LOGS folder on the Nuvi. Each time you turn the Nuvi off and back on a new log will be created.
To view your trips logs in S&T 2010, attached the 1490 to your computer. Open S&T2010 and go to the menu item Data - Import GPX File. Point to the .system/Logs/gpx folder on the Nuvi and load the GPX files into S&T. Each file will create a blue line on the S&T map representing the track you took. All gpx files loaded can be saved as a single gpx file using Data - Import to GPX file in S&T.
There is one thing you will need to do in Windows to be able to get to the .system folder. This is a hidden folder on the Nuvi so to make it visible you need to alter the Windows Folder View Options so that all hidden files and folders are visible and the "Hide Protected Operating System Files" checkbox is 'unchecked".