\label{fig:longitudinal} A possible scheme to obtain longitudinal beam polarization at high energies  ($E_{\rm beam} \gg m_{\rm Z}/2$ ) with TLEP. Taking advantage of the low magnetic field in the arcs, the polarization is generated dominantly by strong asymmetric wigglers of opposite polarities (AW1 and AW2) in two halves of the ring. The transverse polarization obtained this way is rotated to longitudinal in the experimental straight sections  in detector D1,  by 90 degrees spin rotators (SR1L, etc.), and brought back to vertical (but reversed) in the following arc, and similarly for the next experimental straight section, D2. The scheme easily generalizes to the situation with four IPs. This scheme generates a spin transport with an integer part of the spin tune equal to zero. The spin polarization of the electrons is shown.  Given separated beam pipes for the  ${\rm e}^+$ and ${\rm e}^-$ beams, they can be exposed to wigglers of opposite polarity, enabling  positron polarization parallel to that of the electrons. In this way highly polarized $\epem$ systems at the collision point can be obtained. Polarization can be reversed by reversing the wiggler polarity. The possibility of depolarizing a fraction of the bunches in this scheme, to provide a normalization of polarimetry from the measured cross-sections, is being investigated. 