Kirkland & Ellis and Gowling WLG have joined Clifford Chance (CC) and Eversheds Sutherland among the firms advising on Network Rail's £1.46bn sale of its commercial property portfolio, a deal that has reached a conclusion after more than two years' work.

The portfolio will be sold to private equity house Blackstone and commercial property management company Telereal Trillium, which are being advised by Kirkland and Gowling WLG.

Network Rail, which has been working with its longstanding advisers at Eversheds and CC, has been looking to raise funds to invest in its railways since last November. The deal, dubbed 'Project Condor', involved a portfolio of 5,200 properties.

Kirkland and Gowling WLG advised Blackstone and Telereal. The Kirkland team was led by finance partner Michael Steele and corporate partner Carlos Gil Rivas, while Gowling WLG's team was led by real estate partner Michael Twining and John Burns in Birmingham, alongside City-based head of rail Giles Clifford.

The CC team has been led by London real estate partners Angela Kearns and Franc Pena, alongside global real estate sector co-head Adrian Levy.

Meanwhile, the Eversheds team was led by London-based real estate investment head Nicholas Bartlett and included real estate partners James Roberts, Andrew Burns and Lynde Marshall, as well as head of tax David Jervis, litigation partner Alison Oldfield and property consultant Stephen Manson.

Bartlett told Legal Week: "We are thrilled to have exchanged on Project Condor – we've been working on this deal for two and a half years now and it's definitely the greatest intellectual and logistical legal challenge we've ever faced.

"Network Rail's property portfolio has been an integrated part of the railway since the 1800s, and only now are they separating the commercial estate from the railway. There were a lot of different things to consider when working on the deal."

Simpson Thacher also advised the joint venture team on financing issues with City real estate partner Tom Lloyd leading for the firm. A separate team, led by real estate partner Wheatly MacNamara, also acted for Blackstone only on the negotiation of the joint venture with Telereal.

Eversheds also recently advised Network Rail on the transfer of Carillion contracts to Amey Rail, a deal that saved hundreds of jobs following the construction company's collapse and for which Eversheds received almost £500,000 in legal fees from Network Rail.

In July, Network Rail announced its intention to appoint four firms to a new legal roster as part of  an "innovation-driven" group of advisers.

Eversheds is also advising the Department of Transport on the renationalisation of the East Coast Main Line, which will see the rail service brought back under government control from Stagecoach and Virgin Rail until 2020, with Herbert Smith Freehills advising the two railway companies.