>1. Which line is the majority carrier for Nova Scotia and/or
>Atlantic Canada?

CN is the only Class 1 railroad that operates in Atlantic Canada.

In Nova Scotia, you have a few shortlines, the Cape Breton and Central Nova Scotia Railroad, the Windsor and Hantsport RR, and there is at least one terminal RR in the Sydney area.

There are no RR's in PEI anymore.

In New Brunswick, you have the New Brunswick East Coast and the New Brunswick Southern shortlines.

If you want to learn more about railroading in Atlantic Canada, I'd recommend joining the yahoo group below and checking out the links below. Some of the pages have great scenic pictures of railroads in Atlantic Canada, that should be enough to sell you!! :-)