It's now easier for Americans to make reservations for Spain's six international Talgo trains.

Renfe, the national railroad of Spain, has authorized an American travel marketing company to make reservations for seats and sleeping cabins as well as sell tickets on the Talgos, which run daily between Madrid and Barcelona and five other European cities: Paris, Geneva, Zurich, Milan and Lisbon.Reservations can be made with Donna Brunstad Associates, 25 Sylvan Road South, Westport, Conn. 06880 (800-468-2546 or 203-454-9780).

Previously, Americans could purchase tickets in this country - from FrenchRail, which represents the Spanish railroads - but they could not make reservations (required before boarding) for seats and sleepers. They had to get in line at the station in Europe when they were ready to travel.

Many of the seats, particularly on the Madrid-Paris Talgo and the Pablo Casals between Barcelona and Milan, both overnight trains, are reserved months in advance.

On the daytime Talgos passengers may choose to travel in first or second class.

On the overnight trains, travelers have the choice of tourist class (four berths to a cabin), first class (two in a cabin with sink and hot and cold running water) and grand class (two in a cabin with private toilet and shower in addition to a sink).

Examples of fares (based on 97 pesetas to $1): Madrid-Paris about $270 a person in double occupancy in first class and $310 in grand class; Barcelona-Milan, $237 in first class, $257 in grand class.