We are pausing our live coverage, but will be keeping across the story, and will reopen this page if there are any major updates this afternoon.

Here are some of the main developments from last night and this morning:

• A man died and 15 people were taken to hospital after two trains collided in mid-Wales at around 19:30 BST on Monday
• The crash happened near the village of Llanbrynmair, in Powys, involving the 18:31 service from Shrewsbury to Aberystwyth and the 19:09 from Machynlleth to Shrewsbury
• Anthony Hurford, a passenger on the Shrewsbury-bound train, told the BBC he felt “pretty shell-shocked by the incident”. “The word that keeps coming to my head is just brutal really,” he said
• The man who died was on the westbound train, travelling from Shrewsbury towards Aberystwyth, Transport for Wales confirmed
• The company’s chief operations officer, Jan Chaudhry-Van Der Velde, said investigators were at the scene looking into the cause of the accident
• He also said early conclusions about what happened would be published “in the next few days”, adding that a full report would likely take several months
• The Rail Accident Investigation Branch, a British government agency, has deployed a team of inspectors to the site

In the meantime, you can keep up with the latest developments in our main news story here.

Elsewhere in Wales, the Heart of Wales line between Swansea and Shrewsbury has been closed due to “slippery rails”.

Transport for Wales said trains running to and from these stations could be cancelled, with disruption expected until the end of the day, urging people not to try and make the journey in both directions.

It said Network Rail has reported “poor rail conditions” on the Heart of Wales line.

As we’ve been reporting, the crash took place on the Cambrian Line on a single track, which is where trains travelling in both directions share the same track.

These lines are often used in more remote areas or on lesser-used lines.

At various points along the railway line, trains travelling in opposite directions are able to pass each other using passing loops.

BBC Wales' Mari Grug has been reporting from near the scene of the crash, with people still in shock about what happened.

The train was travelling on the Cambrian Line, which runs between Shrewsbury in Shropshire, England, and either Aberystwyth in Ceredigion, or Pwllheli, in Gwynedd.

Aside from being a single track railway, the Cambrian Line was the first in the UK to use a new kind of signalling system.

The European Rail Traffic Management System (ERTMS allows trains to pass each other at reduced distances on single track railway lines.

The pilot scheme was installed on the Cambrian Line in 2011 and has received several updates since.

There is currently no indication that the signalling system had anything to do with Monday’s crash.

Image source, Google

The railway line where the crash took place has been closed, with Transport for Wales cancelling all services.

This means trains between Shrewsbury and Aberystwyth are cancelled until further notice.

A rail replacement service is in operation, but due to road closures, is unable to call at Caersws station.

However, services between Shrewsbury and Pwllheli will run as normal.

The rail disruptions are expected to continue for the next few days while investigations continue.

Meanwhile, the A470 between Carno and Commins Coch has also been closed, with motorists urged to avoid the area and find alternative routes.

Maryam Eslamdoust, general secretary of the transport union TSSA, said “safety is always the number one priority on our railways and therefore it will be vital to gain a detailed understanding of what happened”.

“Our union is greatly saddened by any loss of life or injury on the rail network and we send our sympathy and solidarity to the families and friends of those involved in this incident,” she said.

Ahead of this afternoon’s statement in the Senedd, Transport Secretary Ken Skates has issued a written statement in which he said “our thoughts are with all those involved”.

Skates also confirmed that the Cambrian Railway east of Machynlleth will remain closed while investigations continue.

“I am extremely grateful to the emergency services who attended the scene and helped our passengers and staff,” he said, adding that safety of passengers and staff is “our key priority”.

Skates also said Transport for Wales is working closely with all agencies, including emergency services and the Rail Accident Investigation Branch, to understand how the incident occurred.

Following the crash, Transport for Wales and Network Rail released a joint statement.

It said: "At 7.29pm on Monday 21 October, two TfW trains were involved in a low speed collision near Llanbrynmair in Powys, Mid Wales.

"Sadly one passenger has passed away, and a number of other people are being treated for injuries at nearby hospitals.

"Our first thoughts are with the family and loved ones of the man who has lost his life, as well as all the other people involved in this incident.

"The Cambrian railway east of Machynlleth will be closed while specialist teams continue their investigations, and we urge passengers not to travel to this part of the network.

"We're extremely grateful to the emergency services who attended the scene and helped our passengers and staff in challenging circumstances. we are working closely with other agencies, including emergency services, to understand how this incident happened and they will have our full support."

David Deans
BBC Wales politics reporter

Wales' Transport Secretary Ken Skates will give a statement to the Senedd on the crash on Tuesday afternoon.

It follows multiple requests for emergency questions from Conservative, Plaid Cymru and Labour politicians.

UK Government Transport Secretary Louise Haigh says she's "incredibly sorry" to hear about the crash.

In a statement, she said: "My thoughts are with all of those involved, and their families. I also want to thank the emergency services who responded so quickly last night and remain on the scene."

She added safety on the railways is her "absolute priority" and the government is working with Transport for Wales and Network Rail to understand what happened.

The crash happened on the Cambrian line on a single track, close to a passing loop where trains travelling in opposite directions can pass each other.

Earlier on Monday, TfW advised passengers that its services were running at reduced speeds through Dovey Junction station - which is also on the Cambrian line - because previous trains reported the track was "extremely slippery", according to PA news agency.

The operator also suspended all services on the separate Heart of Wales line on Tuesday "until further notice" due to "poor rail conditions".

Leaves can lessen trains' grip and cause major disruption by sticking to damp rails and becoming compressed by train wheels, creating a smooth, slippery layer similar to black ice on roads.

Image source, PA Media

According to Liz Saville Roberts, the signalling system in place on the railway in the area where the accident happened may need to be “looked at”.

"Obviously we are speculating about what is happening at the moment," said the Dwyfor Meirionnydd MP on Radio Cymru's Dros Frecwast programme.

"Maybe there will be early questions about the signalling system - it's a system they call ETCS and the Cambrian line was one of the earliest; the ETCS system has been on that line since 2011.

"That system of controlling the signalling of the trains is being rolled out as we speak on the main lines throughout Britain, so it is very important that we get to the bottom of what has happened."

Pictures from the scene on Tuesday morning show the train carriages and investigators.

We’ve been hearing more from Transport for Wales’ chief operations officer Jan Chaudhry-Van Der Velde this morning.

He said that investigators were at the scene and would publish early conclusions about what happened “in the next few days”.

"Then they will produce a full report once they’ve looked at every aspect of the evidence, and that normally takes several months to come,” he said.

Simon Browning
BBC business reporter

The Rail Accident Investigation Branch (RAIB) deployed a team of inspectors to the site of the crash in Llanbrynmair, in Powys, last night.

This was an initial deployment, and once the site is inspected, decisions will be made on the need for further resources.

The primary aim of the RAIB team is to gather evidence and work through the crash site, and an update is expected shortly.

The RAIB is a British government agency that independently investigates rail accidents in the United Kingdom in order to find a cause, not to lay blame.

In the initial aftermath of the crash, the RAIB inspectors will be on site to interview all witnesses, examine the trains and tracks and gather all digital evidence, such as CCTV if it exists on the trains.

There should be “on train data recorders” fitted to the trains involved - they are like a “black box” and would gather anything that had been happening.

After an incident, the data can be downloaded and analysed.

The RAIB will then be trying to determine what caused the accident and would then make recommendations.

Generally speaking, the RAIB would aim to complete an investigation within a year of the occurrence.

Image source, Transport for Wales

Chaudhry-Van Der Velde also stressed that "rail as a mode of travel is an order of magnitude safer than some of the journey we take on the highways”, repeating his view that "we have one of the safest railways in Europe".

“So it is extremely shocking when this sort of thing happens,” he said.

He also said he expects disruption to trains in the area to continue for the next few days while investigations continue.

The man who died in the crash was on the westbound train, travelling from Shrewsbury towards Aberystwyth, Transport for Wales has confirmed.

Chief operations officer Jan Chaudhry-Van Der Velde told BBC Radio Wales Breakfast that he could not say much about the causes of the accident, but that investigators were at the scene “looking at all aspects of what could have caused this”.

He also said that “we have one of the safest railways in Europe in this country”, as well as highly-professional accident investigation organisations.

BBC Wales' Craig Duggan has been reporting from the scene of the crash this morning.

You can watch his latest update below.

BBC Radio Wales

The incident was described it as “tragic” by MP for Montgomeryshire and Glyndŵr Steve Witherden, who thanked the emergency services for their work.

“My thoughts are with the family of the man who has died and all 15 of those who are injured and had to be hospitalised," he said.

“I think the people involved and their families will want answers as soon as possible but I also think it’s important that we don’t speculate and we let the investigation carry out it’s work."