The High Court has rejected Heathrow Airport's bid to charge Crossrail for its trains travelling to the airport.
Heathrow said it was "disappointed with today's ruling" and is considering its next steps.
There had been a dispute over whether Crossrail trains should be charged for each time they travel to Heathrow Airport, which the airport was seeking from Transport for London (TfL) which runs the Elizabeth Line.
Crossrail, now known as the Elizabeth Line, will run from Reading and Heathrow in the west to Shenfield and Abbey Wood in the east.
Part of the line will run on track built by Heathrow owners, who use it for the Heathrow Express service. The airport spent £1bn building the line 20 years ago to connect Heathrow to the Great Western track. It wanted to recoup some of the costs of the link.
Previously, the Office of Rail and Road (ORR) had decided Heathrow couldn't charge trains for using the line, saying it would cost around £42m a year.
The airport had said it wanted to ensure "track access charges were fair". It took the decision to the High Court for a judicial review, with the court dismissing Heathrow's application today.
The ORR said:
We welcome this judgement and we will now work with all the affected parties to enable Crossrail services to start running as scheduled into the airport.
"As the independent regulator for the UK’s railways, we have a statutory role in ensuring charges to run trains on relevant networks are underpinned by evidence and comply with legal requirements," it said.
A Heathrow spokesperson said: “Heathrow is committed to increasing sustainable public transport to the airport – that’s why we invested in Crossrail, built the Heathrow Express rail service, support Piccadilly Line services to the airport, and subsidise Europe’s largest free bus network."
We are looking forward to the arrival of Crossrail in May 2018 as part of our plans to treble Heathrow’s rail capacity by 2040 and put the airport at the heart of an integrated transport network in London.
While we are disappointed with today’s ruling and are considering our next steps, both Heathrow and Network Rail agree that track access charges must be fair to encourage future private investment in the rail network.
There had been concerns that should the decision go in favour of Heathrow, Transport for London (TfL) may have opted not to serve the airport at all.
Howard Smith, TfL’s operations director for the Elizabeth Line, said:
“We welcome the court’s judgement to uphold the Office of Rail and Road’s original decision on the charging levels for Elizabeth line services to Heathrow.
“We look forward to working swiftly with Heathrow to conclude final details of access arrangements for Elizabeth line services."
Four Crossrail trains an hour are planned to run between Paddington and Heathrow terminals 2 to 4, from May next year.