Celia Hatton

And the massive steel girders that came down off this high-speed railway line that they're constructing here

down onto the passing train.

There have been a lot of heavy cranes coming in here, lorries taking out the debris from the accident.

At the same time, we've had visits from people inspecting, checking what might have gone wrong, and some of the relatives have also come down here.

relative to those who died on the train, just to see the site of where it all happened.

There is an active investigation apparently ongoing.

The government ordered one immediately.

The railway authority says they expect to complete their first inquiry within two weeks.

But already people are raising serious questions about what was going on here.

One engineer saying that the train should never have been passing on the old line underneath this high-speed rail when they were carrying out the difficult manoeuvre of extending these gantries that helped construct the train.

These elevated railway people are asking for answers.

And there's a big question about how much it's going to delay this already much postponed project, which is going to eventually link the Thai capital Bangkok with China.

This is a prestige project.

It's meant to be a showcase of Chinese and Thai engineering working together.

Obviously, with what's happened here, that's a huge setback.

to the reputation of the people building this... and indeed to Thailand's plans to modernise its infrastructure.

You can see these kinds of building sites... and these kind of ambitious infrastructure improvements... going on all over the country.

And we've heard that only today, this morning, the day after the accident... there's been another very similar accident... on a major road improvement project south of Bangkok... which suggests that there are lingering problems with safety culture...

in this country that still need to be addressed.

Jonathan Head.