A railway line aimed at improving travel after major events in Cardiff has been cancelled.
The Welsh government pulled the plug on the plan, saying it no longer offered value for money.
Transport for Wales (TfW) says it cannot get back £10m spent on preparing to build the track at a steelworks near Newport.
But Senedd opposition parties said public money had been lost on the project.
Under the plans, extra trains could have waited on the 1.6km-long line near the Llanwern steelworks when big crowds of fans were expected at venues such as the Principality Stadium.
It would have provided additional capacity, making transport run more smoothly.
In its latest annual report, TfW said the £10.54m spent on the project since 2018 was "now considered irrecoverable".
The company said other plans to open new commuter stations around Newport and Cardiff, including at Llanwern, will go ahead.
There have been difficulties with transport to and from events in Cardiff in the past, including when Ed Sheeran played at the Principality in 2022.
More big-name acts are lined up there next year, including Taylor Swift and Bruce Springsteen.
Cardiff has also been announced as a host city for the 2028 Euros.
Sarah Hemsley-Cole, who runs a Cardiff-based event production company, said the city had "really fragile transport infrastructure".
"There's always a great push on sustainability and I don't think we really have the solutions here in Wales to deliver a robust transport network to support the events that we have," she said.
Football fan Evan Powell, 20, of Cefn Hengoed, Caerphilly county, said that while delays on match days were inevitable, overcrowding was the biggest issue.
"The amount of times that a two-carriage train has turned up at a platform with hundreds of people waiting on… you're either getting refused to travel back or you're stuck in the most uncomfortable train ride that could be potentially dangerous," he said.
Chris Medlicott, 45, from Aberdare, took his son Owen, five, to his first Wales rugby match at the Principality on Saturday and said train passengers were "irate" due to how packed it was.
"I'm dreading going back," he said.
"I don't know why they don't put extra carriages on when it's going to be busy."
Also attending the Wales v Barbarians match, Shelli Docherty, 44, said her 15-minute train journey from Pontyclun with son Marcus and husband Doc was "absolutely packed".
"The carriage was completely full. There was kissable distance," she said.
"Leaving a couple of hours before kick-off time, I think we've left it a bit late to be honest."
Warren Beck said his son and grandson stood all the way from Gowerton to Cardiff because of the "absolute chaos" of only three carriages.
The Welsh government said a review had concluded the line "would not provide value for money".
"TfW is introducing brand new trains to their fleet to help improve resilience and meet increased demand across the network on major event days," it said.
Ministers recently announced a big cash injection of more than £125m for TfW.
This year it emerged the cost of the South Wales Metro had risen more than £260m to £1bn.
Rail expert Andrew Potter, of Cardiff University, said there was a "fixed pot" of money and rising construction and energy costs had hit the industry.
"If there's something that's only going to be used occasionally and potentially you can work around with other fixes it seems pointless to invest in that when there are bigger priorities," he said.
TfW said the Welsh government had initially asked it to develop the scheme in 2017, and to look at a new station.
"However, following detailed development work, including feasibility, design and enabling works, it became clear the costs associated with the project would be significantly more than initial estimates," said TfW.
"The business case for the scheme was challenged in light of the changes in post-covid demand and wider pressures on budgets.
Money spent will result in "other benefits which have been transferred as part of the wider work which was developed," including the plan for the new Llanwern station.
Welsh Conservative shadow transport minister Natasha Asghar said to "essentially write off" more than £10m was "completely irresponsible".
"I worry the shambolic trains here will be an embarrassment for Wales on the world stage when we host the Euros in 2028," she said.
Delyth Jewell of Plaid Cymru said public transport should be the first choice for fans but that was "nowhere near the case".
"It's disappointing, therefore, to see that this plan to increase the capacity has been shelved and so much money lost," she said.