Business on London rail services has been hit by the recession
Transport firm FirstGroup has reported a 31.7% rise in annual profit to £200m, helped by its North American business, which runs 60,000 yellow school buses.
However, profits at its UK rail business, which runs First Great Western, First ScotRail and First Capital Connect, fell more than 20%.
The company said that it had delivered a "robust performance" in a "turbulent macro-economic environment".
But FirstGroup said it was not immune to the global economic downturn.
The company said pre-tax profits totalled £200m ($306m) in the year to the end of March, compared with £151.9m a year ago.
It said operating profit at its North American business, which also includes the Greyhound bus service, rose by 72.5% to $483.5m (£316m).
The Aberdeen-based company said much of its operations in North America are contract-based, making them less vulnerable to the slumping economy.
However, it said that operating profit at its UK rail division was down 21.5% to £94.2m as the recession hit its franchises serving London.
"No business can regard itself as completely immune from the global economic downturn and across the sector there will be challenges to overcome," said Sir Muir Lockhead, FirstGroup's chief executive.
The company is also the UK's largest operator of bus services.