It definitely is true, these are electrified lines and rolling resistance is low. For equivalent distances elsewhere emissions are 80-90% lower with rail over air transport. With the potential for solar in SoCal there is no reason this could not be even better.

Dividing the landscape is a separate issue. It can be mitigated against (tunnels, habitat bridges, route planning), but alone it's not an excuse to stick with emission heavy modes of transport.