ABQAIQ, 11 March — Three people were killed and another was injured when a train carrying oil containers rammed into loose railroad cars of a goods train here yesterday evening, officials at Saudi Railways Organization said. Among the dead are the driver of the train, his helper and a military officer.

A Saudi Aramco security official was injured during the rescue operation.

The officials said that both the trains were going from Dammam to Riyadh. An inquiry into the accident has been ordered. The officials are at a loss over the cause of the accident, which many said was horrific.

According to sources, many railroad cars were mysteriously uncoupled from the rest of the goods train (No. 115) and the train proceeded to Riyadh without noting this.

Meanwhile, the train (No. 117) carrying oil had left Dammam nearly an hour after the goods train, and was put on the same track.

The driver of the train No. 117 failed to react quickly on seeing the uncoupled cars on the track, and rammed into them.

The sources said the accident occurred at 9 p.m. The collision sparked a fire which spread very fast. Although the fire was brought under control, firefighters were still struggling to extinguish it.

Just a few kilometers from the site of the accident is the residential quarters of Saudi Aramco employees.

All the casualties were from train No. 117. The injured Aramco employee has been shifted to hospital. His condition is reported to be stable.

The authorities have yet to ascertain the damage. The accident hampered train service between Dammam and Riyadh. However, authorities hoped that the tracks would be cleared soon and services restored.

Authorities are puzzled over how more than 20 railroad cars of the goods train got disconnected without the driver’s knowledge or anyone detecting it.

The rescue team from Dammam was quickly on the site and work to clear the tracks is in full swing.

Two people were killed in December last year when a Dammam-bound passenger train derailed some 150 kilometers from Riyadh.

Train services on the Riyadh-Dammam route were disrupted during Eid Al-Fitr holidays — the busiest days of the year —as a result of the derailment.

Train accidents are rare in Saudi Arabia, which has only one railway line — a 450-kilometer link between Riyadh and Dammam.

The Kingdom is currently studying plans to build around 2,000 kilometers of railways to link the east and west coasts and the minerals-rich north with Riyadh.