Four people were seriously injured and 31 slightly hurt when an Athens-Kalamata train was derailed between Tripolis and the village of Leontari yesterday morning. Several passengers charged that the train was speeding. The Hellenic Railways Organization (OSE) said both the train and the track had recently undergone maintenance. OSE said that according to an initial evaluation, the accident may have been due to human error but that a final ruling would be made after an official investigation. Transport Minister Christos Verelis and OSE Managing Director Constantinos Yiannakos visited the scene of the accident with other railway officials. Of the 37 passengers, 35 were taken to nearby hospitals. Only four had sustained more serious injuries (two of them had broken legs) but were not considered to be in any danger, according to OSE. The train had left Athens at 6.29 a.m.