A four-year-old girl has died in hospital after the car she was travelling in collided with a train.
Emma Lifsey, who was airlifted to Sheffield Children's Hospital following the collision, was pronounced dead in the early hours of Wednesday morning.
In a statement, Emma's parents said their four-year-old "meant the world to us. She was our much-loved daughter and a baby sister to her 11-year-old brother Jack.
"We are still trying to come to terms with the terrible incident on Tuesday afternoon and there are no words that can properly express how utterly distraught we are," said Mark and Zoe Lifsey.
The couple, from Haxey in Lincolnshire, thanked people for their messages of sympathy and support but asked "to be left to grieve in private at this acutely difficult and sad time for us."
The collision happened at Beech Hill crossing, Springs Road, Misson Springs, Nottinghamshire, yesterday.
The driver, a 67-year-old woman, was taken to hospital in nearby Doncaster with neck injuries and bruising.
She remains in hospital in a stable condition.
A British Transport Police (BTP) spokesman said: "The police investigation into the incident is ongoing and remains very much in the early stages.
"Officers are working hard to establish the full circumstances surrounding the incident, including how the vehicle came to be on the tracks at the time.
"This will include speaking to any witnesses to the incident, while specialist officers will also look at evidence from the scene and the car in question, a black Volvo which has now been recovered.
"The train, a Lincoln to Doncaster service, was damaged but remained upright and on the tracks. There have been no reports of injuries to passengers or staff on board."
The spokesman said the Rail Accident Investigation Branch (RAIB) and Office of Rail Regulation (ORR) have been notified.
The ORR confirmed it has begun working with police to investigate the crash.
The scene of the collision is a crossing about two miles east of the nearest village of Blaxton, on a small country lane which connects the B1396 to the village of Misson.
Speaking at the scene yesterday, Inspector Andy Selby, from BTP, said he could not comment on whether the barriers and lights were working correctly.