Ti represents a substitutional dopant in Nb and at low temperatures acts as hydrogen trap. For Nb 0 . 9 9 9 Ti 0 . 0 0 1 H 0 . 0 0 1 at 1.5 K we observe a pronounced (ground state) tunnelling peak at 0.4 meV and a second weak peak at 0.4 meV in high resolution neutron spectra. The vibrationally excited state has been studied by neutron energy loss spectroscopy on Nb 0 . 9 9 Ti 0 . 0 1 H 0 . 0 0 9 4 ; the (fundamental) vibrational peak around 110 meV exhibits a splitting into three tunnelling lines separated by about 4 meV. Both tunnelling phenomena indicate hydrogen delocalization over four (or perhaps six) sites. This conclusion is supported by muon spin relaxation measurements between 10 and 200 K and a QENS study at 150 K, where in both cases a localized motion (jump rotation) of the light interstitials over four sites was found.