MADRID, Jan 19 - Sunday's train collision and derailment in southern Spain killed at least 39 people and left 122 injured, with officials highlighting the "tremendously strange" nature of the accident on a straight stretch of railway.

Here is what we know so far:

The accident happened at 7:45 p.m. (1845 GMT) near the town of Adamuz in the province of Cordoba, about 360 km (223 miles) south of the capital Madrid.