CVC bought PKP Energetyka from Polskie Koleje Państwowe (PKP) in July 2015 for Z1.97m (€477m).
The company provides nationwide maintenance and emergency response services to the railway network, operates fuel stations for diesel locomotives and is also involved in electricity and gas reselling.
In that same month CVC borrowed $2.9bn from Lloyds, BNP Paribas, NatWest and Standard Chartered, according to Dealogic, although it could not be confirmed by the time GlobalCapital went to press that this was money used to buy PKP Energetyka.
The new refinancing loan is being led by ING and is due to close within the next two months, according to bankers close to the deal.
The deal would be the second from Poland this year. The first was also to do with an acquisition by CVC of Polish supermarket Zabka.