These are the standard MSTS resolutions: all are 4:3 aspect ratio ( a composite image from my desktop PC in response to a question on Railpage a few years ago):

You can set screen resolutions on laptops to eliminate distortion in MSTS: here's an example of a Compaq laptop (I purchased this just to see how bad Vista and MSTS are - and there's nothing wrong with Vista, but I digress).
Right-click on the screen, select "Graphics Properties", then "Display Settings", thus:

Under "Display Expansion", click on "Aspect Ratio Options" (arrow #1 above).
Select "Maintain Aspect Ratio", thus (arrow #2):

This will give you the largest possible MSTS viewpoint with black bars down each side of the screen (much like a 4:3 TV programme on a wide-screen TV) - note you now DO NOT need the
-vm:w parameter (see below):

BTW, if you do use the switches shown above, you don't need to use 800,600,32 in the command line as that forces MSTS to use 800x600 32-bit. Set the screen display in MSTS Options to the largest option available and save: MSTS will open with that resolution every time. The command-line switches ARE useful if you have mini-routes that you want to run at a different resolution to your master MSTS as mini-routes take their initial resolution settings from the registry - unless over-written in the command line (for example, you're working on an activity in a mini-route and want to be sure AE opens in 16-bit to avoid "issues").
I'll grab my other laptop and put up screenshots of changing its display shortly.
EDIT #1: actually you may want to set your windowed MSTS screen resolution to a figure one step lower than the maximum your wide-screen can display: if you don't, you may find that the bottom of the MSTS window is off the desktop.
EDIT #2: As promised.... from my other laptop: right-click on desktop, select "nVidia Display" then "Laptop Display". Select "Digital Flat Panel Settings" ans then select "Fixed Aspect ratio scaling".

I'll kidnap my wife's Dell laptop tonight and see what its display settings are and post some screenshots - if I live
HTH.