The passenger train involved was NOT a high speed train. It was a loco-hauled train with very modern cars (possibly from or under license from Siemens). The locomotive is a general purpose unit built in Turkey under a license from Hyundai Rotem. Its maximum speed is (depending on the source) 120 km/h or 140 km/h. The consist could have been certified for higher speeds.

From other sources, the main collision was with a maintenance vehicle, but a suburban train must also have been involved. It would not be a surprise that the maintenance work took longer, and the line should not have been opened yet (pure speculation, only based on the time of the day of the accident).

So, this accident most likely could be categorized as a freak accident, unless the officials find other reasons. It looks as if not the collision caused most damage, but the overpass which got hit and collapsed on the train. The train speed must not have been very high, as it looks as if the second car is the most damaged one.

In any case, this accident has nothing to do with HSR at all.