Angel is currently owned by a consortium of investors from Australia, Canada, Luxembourg and the UK, which bought the company from the Royal Bank of Scotland in 2008.
The firm is reported to have appointed Citigroup to lead a sale of the company.
It said in a recent statement that the decision “to investigate the possible sale” would have no impact on operations. “For us, it is business as usual,” the firm said.
Angel added that all contracts currently in place with train operators, and those in the pipeline, will be honoured.
Eversholt was sold to Hong Kong-based billionaire Li Ka-Shing in January, while Porterbrook was bought by a consortium including Allianz Capital Partners in October last year.
Angel Trains declined to comment yesterday.