Amtrak is offering two reduced fare plans through May. The "All Aboard America" regional fare and the "One Way Plus $7" excursion fare both provide substantial discounts on regular ticket prices, particularly for long trips.

The "All Aboard America" fare is a flat ticket price for travel within, or between Eastern, Central and Western regions of the United States.For a period of up to 45 days, and with up to two stopovers plus the final destination, an adult may travel in one region for $149, in two regions for $199 and in all three regions for $249. Children from 2 to 11 travel for half price.

Under the "One Way Plus $7" fare an adult can buy a one-way ticket for a journey costing at least $65 and pay only $7 for the return ticket.

The fare is not available on trips costing less than $65 for a one-way ticket or over the Christmas holidays.

Neither fare is available on Amtrak's Metroliner and international train service, or in conjunction with other discounted fares. More information: 800-872-7245; Amtrak Distribution Center, Post Office Box 7717, Itasca, Ill. 60143.