The announcement to resume the service was made after Pakistan released an Indian pilot shot down during an aerial clash over the disputed Kashmir region last week.
Nuclear-armed Pakistan and India both carried out aerial bombing missions last week and on Wednesday fought a brief dogfight in the skies.
The number of train passengers had fallen drastically after relations soured following an attack in Pulwama in Indian Kashmir, in which at least 40 Indian soldiers were killed.
India blames the Pakistan-based Jaish-e Mohammad for the attack.
The Samjhauta (Hindi for “Agreement”) Express train service began on July 22, 1976 under the Shimla Agreement that settled the 1971 war between the two nations.
The train normally runs between the two countries twice a week. On the Indian side, the train runs from Delhi to Attari and on Pakistan’s side, from Lahore to Wagah.
(Production: Louisa Naks)