Private-equity firms are on track to raise a record amount for infrastructure investing in 2018, as money managers bet on the growing need to upgrade and expand the world’s railroads, natural-gas pipelines and data centers.

The firms collectively raised $68.2 billion in the first three quarters of the year, up 18% over the same period in 2017 and already surpassing the $66.2 billion they amassed in all of 2016, according to data from Preqin.

Leading the charge are KKR & Co., Stonepeak Infrastructure Partners and I Squared Capital, which each raised a roughly $7 billion investment vehicle this year.

The numbers are set to swell even more as the total doesn’t include the $5 billion raised so far by Blackstone Group LP in the initial phase of its planned $40 billion infrastructure fund. Meanwhile, two infrastructure powerhouses, Global Infrastructure Partners and Brookfield Infrastructure Partners, which raised $15.8 billion and $14 billion funds, respectively, in 2016, are already targeting new pools of roughly $20 billion each.

Institutional investors such as pension funds have been allocating more money to infrastructure, attracted by its reputation for steady returns, which typically fall between safer fixed-income securities and riskier private equity. That is especially appealing with interest rates still near historically low levels and equity prices close to all-time highs.