Depicts the seal of the United Mexican States.

The Seal of the United Mexican States is a modified version of the national coat of arms, with the addition of the full official name of the country Estados Unidos Mexicanos, in a semi-circular accommodation in the upper part of the seal. Current and past Mexican peso coinage have had the seal engraved on the obverse of all denominations.

The coat of arms depicts a Mexican golden eagle perched on a prickly pear cactus devouring a rattlesnake. To the people of Tenochtitlan this would have strong religious connotations, but to the Europeans, it would come to symbolize the triumph of good over evil (with the snake sometimes representative of the serpent in the Garden of Eden).

At the center, the image of the reverse of a United Mexican States coin, 5 Pesos 1950 (KM# 466), commemorative coin of the inauguration of the Southeast Railway (radiant sun flanked by palm trees above train); at the upper side, parallel to the coin frame, the legend NUMISMATIC HERITAGE OF MEXICO; on the left side, the Mexican mint mark, while on the right field is the $100.

In 1950, the former President, Miguel Alemán, inaugurated the Southeast Railway, the most important infrastructure work that integrated the Yucatán peninsula to the rest of the country. This magnificent work began under Lázaro Cárdenas administration and was continued by Manuel Ávila Camacho.

5 Pesos 1950 silver coins were badly distributed and most of them were stored in Mexico City Mint. Later over half of them (100 000 pieces) were melted to be used for the 1968 Mexican Olympic 25 Pesos. This effectively made Southeastern Railroad 5 Pesos one of the rarest mid-1900s silver coins in Mexico.