I have just found a rate of $456.00 per couple on 3 days train travel pass in France. Is that a good rate or is there
only 1 train line that can be used??
Depends on where you're travelling, and when. The three-day-in-one-month France Railpass (second class) is a standard price at $227.00 U-S, offered by RailEurope, which is co-owned by the French and Swiss national railway systems. You might want to check out point-to-point fares for your intended destinations at http://www.sncf.fr/indexe.htm. Enter your starting point and destinations and see how much the fare is. Early-booking fares are certain to be cheaper, but they're non-refundable and non-exchangeable, so you're locked into those journeys on those days. However, even the regular fare may be cheaper, again depending on your itinerary.
P.S......all rail journeys are under the auspicies of the SNCF, the French national railway company.
Thank you.