Events taking place to mark 25th anniversary of Ladbroke Grove rail disaster
More than 220 were injured when a rush-hour train collided with a high-speed train
Memorial events will be held on Saturday to mark the 25th anniversary of the Ladbroke Grove rail disaster.
Thirty-one people were killed and more than 220 were injured when a rush-hour train collided almost head on with a high-speed train around two miles from Paddington station, west London, shortly before 8.10am on October 5 1999.
It was one of the most catastrophic rail incidents in recent UK history.
A wreath-laying ceremony will take place in a memorial garden near the crash site at 8am, followed by a service of remembrance at 11am at St Helen's Church, North Kensington.
Around 250 people are expected to attend, including relatives of the victims, survivors and representatives from the emergency services, local authority and trade unions.
The events will be led by the Rt Rev Dr Emma Ineson, Bishop of Kensington.
An inquiry into the disaster revealed that the Thames service travelling from Paddington to Bedwyn in Wiltshire had gone through a red signal before crashing into the London-bound high-speed First Great Western train.
Mark Phillips, chief executive of rail industry body the Rail Safety and Standards Board, said: "The rail industry experienced one of its darkest days at Ladbroke Grove 25 years ago.
"The legacy from this tragedy is that lessons learned, collaboration, hard work and modern technology have made Britain's railway one of the safest in the world.
"We remain vigilant and continually strive for further improvements. By working together, we can reduce the risk of a catastrophic train accident happening again.
"Our thoughts remain with the families and friends of those who died, those injured, and those who survived and live with the memory."
The general secretary of train drivers' union Aslef, Mick Whelan, who is attending the memorial events, said: "As an industry we will never forget those who lost their lives, those who were injured, and all those families who were impacted and who suffered because of the Ladbroke Grove rail crash.
"And we should never forget the lessons that we learned in what is, and what will always be, a safety-critical industry."
Dangerous incidents of trains passing red signals have decreased since the introduction of safety improvements such as the train protection and warning system.
Office of Rail and Road figures show there were 287 signals passed at dangers - when a train passes a stop signal without permission - on Britain's railway in the year to the end of March.
That is compared with 593 in 1999/2000.