Real Investment is calculated as nominal investment (http://research.stlouisfed.org/fred2/series/NINV) divided by investment deflator (http://research.stlouisfed.org/fred2/series/INVDEF) multiplied by 100.
For additional details see: R. DiCecio (2009). "Sticky wages and sectoral labor comovement," Journal of Economic Dynamics and Control, 33(3): 538-53. (http://dx.doi.org/10.1016/j.jedc.2008.08.003).
Source: DiCecio, Riccardo
DiCecio, Riccardo, Real Investment [RINV], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/RINV/, November 28, 2015.