Magnetic excitations in 1-dimensional (1D) antiferromagnet R2BaNiO5 (R=Nd and Y1-xNdx) has been investigated by means of both polarized and unpolarized neutron scattering technique. Observed spin gap at 1D zone center above Neel temperature was confirmed to be originated by the same as Haldane gap obtained in the pure Haldane system Y2BaNiO5. In the 3D ordered region where the magnetic Bragg peaks clearly develop, the gap energy shows the sharp upturn at around T-N and increases linearly with decreasing temperature. Polarized neutron experiment reveals the coexistence of both quantum 1D Haldane and 3D long range antiferromagnetic (AF) phases.