The Rain in Spain comes with two derailed trains

[Westham67]

https://www.bbc.co.uk/news/articles/clye22ljxw4o

I would say just from that photo, I know what happened. No maintenance has been carried out for years. The track is in a cutting, and no drains have been cleaded they have not even tidied the ballast up. Water will wash away the fines in the ballast toward the middle of the tracks. When the train came through that area, the inner rail got pushed down, and the train fell off and took out the train coming the other way. As always ready to parle 

I have some shit track in my time, but the state of that is a fucking disgrace

[Westham67]

The outer rail on the LH track, as you look at it, should not be higher than the inner rail; it should be "Flat" on straight track. The carriage wheels will unload from the rails, which is called a twist and when trains fall off 

Due to carriage lengths and the distance between train wheels, some of the twist measurements are 3 meters and 6 meters. If the LH rail is + 3 and the RH rail is -5 from the level of 0 for straight track (Cant or banking on the road), then you have wheels unloading from the rail. Its is complacency which is a killer

[RBshorty]

Possibly, but it looks like the tack has not been tamped (The Ballast has not been compacted under the sleepers). Its not aligned like new work either

This. However it doesn’t just go.  It would have been a known “Rough Spot.” And would have been reported as such.? Don’t know until the tapes and records start coming out for sure. But Spain is starting too get a dodgy reputation with its rail safety.

[Westham67]

Possibly, but it looks like the tack has not been tamped (The Ballast has not been compacted under the sleepers). Its not aligned like new work either

[Mike Oxsaw]

I thought that I read that there had been work done on that particular section less than a year ago.